Conducting a Sound Sweep for Search & Rescue By: Martin Colwell

Conducting a Sound Sweep

Instructions to Search Teams  

By: Martin Colwell  Aug. 1996

(posted on FSAR blog with permission from M. Colwell)

Introduction:

The Sound Sweep is an efficient form of grid-searching that utilizes sound to help find a missing person. Recent Sound Sweep field experiments (ref 1,2,3) have shown that there is a high probability of searchers finding a missing persons at three to four times the searcher spacing required for a normal, summer visual grid search. This means that search teams may cover a three to four times larger search area if they employ sound while conducting their grid search.

Compared to earlier historical data (ref 4) the Sound Sweep area coverage is up to 6 times greater in dense coniferous forest in summer, 9 times greater (at a low voice-response volume) in winter and 23 times greater in sub-alpine forest in winter. The Sound Sweep therefore is an important new tool for field teams to employ, both for area searching and as they conduct their initial hasty (trail) searches.

Limitations:

The Sound Sweep technique is based upon the presumption that a missing person will respond with sound, usually by shouting, if he/she hears a loud sound generated by the searchers. For the technique to work the Sound Sweep must be conducted while the missing person is responsive and still capable of an audible (typically, shouted) response. This means that Sound Sweeps should be conducted within the first few days, and preferably within the first 24-48 hours, of search notification.

Procedure:

Base Radio Operation

A base radio is set up in a location that will have good coverage of the search area or route. A radio operator will repeatedly broadcast the following radio prompt to all the searchers: "Four, Three, Two, One, Blast ...". This prompt will be re- broadcast typically every one or two minutes - for the entire duration of the Sound Sweep.

(An assistant radio operator is usually required to relieve with the radio-prompt duties).

See the attached table for the required prompt intervals.

Alternatively electronic ‘beeper’ devices have been built that automatically insert four short warning tones then one long (‘blast’) tone into the base radio transmissions, to automatically prompt the searchers to perform their whistle-blasts at the required prompt intervals.

Note: These radio-prompt broadcast intervals, for both area and trail searching, have been chosen from the POD search data to ensure there is a 100% probability that searchers will hear an audible voice-response from a missing person. These radio-prompt intervals correspond to a distance travelled betweens whistle blasts of not more than:

18m (59ft) in Dense Coniferous Forest - in summer or winter 60m (197ft) in Open Sub-Alpine Forest - in winter.

Sound Sweep Field Operation

Sound Sweep Area Searching:

Every searcher in the team is equipped with a VHF radio, a map, compass and a loud whistle. (The Fortron Fox40 whistle is recommended).

The search team members are spaced out at very wide spacings, as specified in the accompanying Sound Sweep Probability of Detection (POD) tables, along the search area baseline. At these spacings the searchers will often not be able to see each other and so radio communication will have to be used to maintain contact between the team members.

Each searcher, upon reaching his/her starting location along the search area baseline, should identify and flag this location and then radio to base that he/she is commencing the Sound Sweep.

There is no need to the searchers to start their sweeps simultaneously.

The searcher shall follow the compass bearing assigned by the search manager. Occasional brief radio communications with other team members, and the team leader, should be maintained, to ensure team safety.

Every time the searcher hears the Base radio warning prompts commencing he/she shall stop, place the whistle in the mouth and perform a simultaneous loud whistle blast on hearing the radio "Blast " prompt. (To preserve hearing it helps to plug the ears during the whistle-blast).

Following the whistle-blast maintain five seconds of radio silence. During this period the searchers stop and carefully listen for an audible voice-response from the missing person. If no audible or visual response is received then the searchers continue travelling until they receive the next radio prompt. The searchers repeat this base-prompted whistle-blast procedure, and listening for an audible response, while they travel the entire search area.

The search manager may request that additional Sound Sweeps be performed, preferably at right-angles to the previous sweep.

These additional sweeps are necessary if the missing persons probability of detection has to be increased.

Sound Sweep Trail Searching:

A Sound Sweep trail search, for a normal voice-response person, approximately doubles to triples the width of the trail-searched ‘corridor’ compared to standard visual searching. This Sound Sweep corridor has a bell-shaped POD profile which starts at 100%POD on the trail, and tapers down to 20%POD at the far edges of the corridor. This sound-swept corridor is approximately 270m(886ft) wide in dense coniferous forest under summer conditions, and 560m(1837ft) wide in dense coniferous forest, or open sub-alpine forest, under winter conditions.

Sound Sweep trail searching uses exactly the same Sound Sweep procedure of regular base-radio prompts, searcher whistle-blasts and listening for an audible voice-response from the missing person, as the team follows its trail or route. Because the team is moving together on the trail only one radio per team is usually required. (Of course the previous area searching instructions of searcher-spacing and following compass bearings do not apply for Sound Sweep trail searching).

The Sound Sweep radio-prompt interval is usually more frequent for trail searching than area searching due to the normally faster travel speeds of searchers on the trails. While the trail search teams may find the frequency of these whistle-blast prompts somewhat inconvenient it is not advisable to extend the period between whistle-blasts much longer than specified in the Sound Sweep Radio-Prompt table, doubling these prompt intervals will drop the probability of hearing a normal voice-response from 100%POD down to approximately 85%POD.

One possible option is to have each member of the trail search team take turns in performing the whistle-blast, and perhaps not stopping while listening for the subject’s voice-response.

The default recommended Sound Sweep Trail Search radio prompt intervals are:

Every 20 seconds on trails through dense Coniferous Forest, (in summer or winter).

Every 1 Minute on trails through open Sub-Alpine Forest (in winter).

Note: Doubling these prompt intervals will reduce the POD of hearing a normal voice-response from 100% POD down to approx. 85% POD.

Sound Sweep Trailhead Searching

Searchers in vehicles and trailheads can also apply the Sound Sweep technique to their search efforts. A radio-equipped vehicle parked at a trailhead or boundary of a search area may perform horn-blasts on cue from the base-radio prompts, simultaneously with the searching field teams. The louder sound generated by the vehicle horn may awaken or alert the subject, who may not have otherwise heard the whistle blasts, particularly if they were asleep or close to noise sources, such wind or rushing streams.

Sound Sweep Road Searching

The Sound Sweep may be used by radio-equipped vehicles searching from a road within the search area. For example, using four radio-equipped vehicles:

The four vehicles are driven along the road until they are exactly 1km or 1 mile apart (depending on whether the odometer reads in kilometers or miles). On hearing the base-radio prompt each vehicle then simultaneously sounds its horn and the driver then listens for an audible response from the subject. If no response is heard the convoy then drive exactly 0.1km (or 0.1miles) along the road using the vehicle odometer to track their distance travelled. The vehicles then stop, wait for the base-radio prompt and then repeat their simultaneous horn-blast. Again the drivers listen for an audible response from the subject, if none is heard the vehicles are then driven another 0.1km (or 0.1 miles) and the simultaneous horn-blast and listening procedure is repeated.

This drive/blast/listen process is repeated until each vehicle has driven exactly 1.0km (or 1.0 miles) i.e. until they have reached the original starting location of the vehicle in front. At this time the 4-vehicle convoy then travels 4km (or 4 miles) further up the road, i.e. until the last vehicle reaches the final finishing position of the first vehicle. At this time all the vehicle drive forward another 0.1 km (or 0.1 miles) and the whole procedure is repeated for another 1km (or 1 mile) and the convoy then moves forward again. Using this procedure a fairly large area adjacent to a road can be searched quickly with minimum manpower.

The POD at 0.1km (100m, 328ft) driving intervals i.e. up to 0.1km either side of the road for normal voice response, is 42% for dense coniferous forest in summer and 62% for sub-alpine forest in winter. For a quiet voice response in subalpine forest in winter the POD is 42%.

The POD at 0.1mile (528ft) driving intervals i.e. up to 0.1miles either side of the road for normal voice response, is less than 5% for dense coniferous forest in summer and 34% for sub-alpine forest in winter. For a quiet voice response in subalpine forest in winter the POD is also less than 5% Clearly a shorter driving interval, such as the 100m, 328ft interval above is preferable to avoid the subject's voice response from becoming inaudible.

Sound Sweep comments:

As the Sound Sweep relies heavily on radio communications uneccessary radio-chatter should be kept to a minimum.

Having large numbers of searchers, all operating radios, raises the possibility that the radio prompt, and particularly the important following five seconds of radio silence, will be masked by radio communications.

Radio communications between the radio-prompts is acceptable but no transmissions should be permitted during the radio-prompt and the following five seconds of radio silence.

The searchers should occasionally perform a radio check with base, especially if they have difficulty hearing the repeated radio-prompts. The searchers may have moved out of good radio contact with base as they travel through the search area or route.

If radio communication becomes poor then the base radio will have to be relocated. This may happen when searchers start, with good communication, on top of a ridge, but lose communication as they move down to the valley bottom. If necessary, plan to have an alternate base radio location in place, ready to restore communication as the searchers move through the search area.

RECOMMENDED SWEEP SEARCH CONDITIONS

--- For SOUND SWEEPS ---

Area Sound Sweep Search Conditions:

Typical Summer Area-Search Speeds in Dense Coniferous forest:

0.4Km/hr ((0.25 miles/hr) in rough mountain forest with moderate to heavy bush, Sound Sweep whistle-blast every 2 minutes.

1.0Km/hr ((0.62 miles/hr) in fairly level forest with light to moderate to bush, Sound Sweep whistle-blast every 1 minute.

Typical Winter Area-Search Speeds on firm snow with most of the bush buried. Dense Conifereous forest: 0.62Km/hr (0.39 miles/hr)

Open Sub-Alpine forest: 0.86Km/hr (0.53 miles/hr) *Sound Sweep whistle-blast every 1 minutes. **Sound Sweep whistle-blast every 2 minute.

for Search Teams' by Martin Colwell. 1991 (3). ‘Planning the Gridsearch’ 1994

Additional Sound Sweep article here: 

 http://specopsblog.blogspot.ca/2014/02/sar-operations-how-to-conduct-sound.html 

 Martin Colwell site:  http://sartechnology.ca/  

Winter Scenario Training, Dec. 9, 2015

Winter scenario training:

FSAR please come prepared with gear and clothing as if, you were just activated for a mid-January backcountry search. We will be training outdoors. 

New FSAR Storage Building, Looking for a Garage Door!

UPDATE 11-22 A garage door has been donated THANK YOU!

A call for building materials!

FSAR is planning to construct a ‘garage sized’ storage building to store the SAR trailer.

The size of this building will be 12’ x 20’.

Tooker construction has offered to donate many of the required materials for the structure but we do need a few additional things:

We are currently looking for a 9’ x 8’ garage door. (Donated 11-22)

As we get further into the project additional needed materials will be listed here on the blog.

Any donations will be greatly appreciated.

Thank you

4-Day Rigging for Rescue Rope Rescue Workshop on MDI

Photos and story by FSAR Pat

On October 19^th through the 22^nd Pat, John, Shannon, and Paul attended Rigging for Rescue (RFR) training on Mt. Desert Island.

The 22 students that participated in the training included members of various MASAR teams throughout the state as well as Acadia National Park rangers. 

Rigging for Rescue is a company out of Ouray Colorado which offers technical ropework seminars that focus on applying critical thinking and systems analysis skill required to competently incorporate ropework and rigging into effective rescue systems.  The 4 day course was conducted by Mike Gibbs, RFR founder, and Leo Lloyd, instructor. 

Each day began with classroom training held at the Seal Harbor Fire Department.  Practical training was held at various amazing sites overlooking the Atlantic Ocean!  

Some of the topics and techniques we covered included:

• Safety factors and rescue safety systems
• Anchor points and systems
• Command and Communication
• Systems analysis and scene size up
• Simple, compound, and complex pulley systems
• Parallel plaquettes
• Radium release hitches
• Rescue belays and hauls
• Pick off’s lowering with a self-belay
• Horizontal and vertical Stretcher techniques on raises and lowers

Many thanks to Steve Hudson of Mount Desert Island SAR for organizing the event, along with Davin and the fellow MDISAR team members for their help with equipment, home baked goodies, and driving directions around the Island!

We also wish to thank the 'Friends of Baxter' organization, the Savoy Foundation and FSAR, for their generous support which helped offset much of the cost of this very productive and informative workshop. 

Largay: Missing AT hiker died of exposure, lack of food and water (Daily Bulldog Article)

AUGUSTA – Skeletal remains found on Oct. 14, 2015, in Redington Township were confirmed through DNA analysis by the state's medical examiner as Geraldine Largay. Her death was ruled accidental, resulting from a lack of food, water and exposure.

An experienced hiker, Largay was last seen on the early morning of Monday, July 22, 2013, at Poplar Lean-to on the AT in Maine.

The Warden Service said that after examination of the remains and working in conjunction with information from investigators on the case, the chief medical examiner determined this was "an accidental death due to lack of food and water and environmental exposure," according to Cpl. John MacDonald, spokesman for the Warden's Service.

The cell phone found in Geraldine’s possession has been examined by the Maine State Police Computer Crime Lab. Information found on the cell phone concluded that Largay reached Orbeton Stream and the discontinued railroad bed crossing in the late morning of July 22, 2013. Shortly after reaching that intersection, she continued north on the AT and at some point left the trail and became lost. The exact location where she departed the trail is unknown.

The remains were found on Wednesday, Oct. 14, by a contractor conducting a forestry survey as part of an environmental impact statement on property owned by the U.S. Navy in Redington Township. The contractor reported his findings to the Navy who subsequently alerted the Maine Warden Service. Personnel to include game wardens, State Police personnel, Naval Criminal Investigative Service (NCIS) investigators, and a Medical Examiner’s Office representative hiked to the scene of the remains Thursday morning Oct. 15.

According to MacDonald, "the scene included skeletal remains and several pieces of clothing and belongings consistent with items known to be in Largay’s possession. The remains were located west of the Maine Public Reserve Land that contains a portion of the AT and about 3,500 feet east of the easterly shore of Redington Pond.

"These findings now bring closure to one of Maine’s most unique and challenging search and rescue incidents," he said.

Geraldine “Gerry” Anita Largay, 66, started her hike on the AT in April of 2013 at Harpers Ferry, W.V.; her trail name was “inchworm.” Her destination was Baxter State Park in Maine. Her husband George Largay kept track of her along the way and made frequent predetermined stops to resupply her.

Map showing Appalachian Trail highlighting Poplar Ridge Lean-to, Spaulding Lean-to and Geraldine Largay’s final location discovered Oct. 14, 2015. (Map courtesy of the Maine Warden Service)

On the morning of Sunday, July 21, 2013 she departed from her husband at the Route 4 AT crossing in Sandy River Plantation near the town of Rangeley. Later that day, she texted her husband and advised she was on top of Saddleback Mountain. Geraldine Largay was last seen on the early morning of Monday, July 22 at Poplar Lean-to on the Appalachian Trail in Maine. She was planning to hike that day to Spaulding Lean-to in Redington Township, approximately eight miles to the north. On Tuesday, July 23, she had planned to continue hiking north from Spaulding Lean-to located in Mount Abram Township to meet her husband who was waiting for her at the Route 27 crossing. She never arrived at that location.

The Maine Warden Service wishes to thank the many law enforcement and EMS organizations, search and rescue volunteers, and local business owners who generously gave their time and resources.

"We consistently see the community spirit in Maine and this is another fine example of a community coming together to assist in helping a person and family in need," MacDonald said.

The Largay family issued a statement: “We wish to thank all of those who gave their time and prayers while searching for our wife, sister, mother, and grandmother. We especially would like to thank the entire Maine Warden Service for their dedication to this case. It became apparent from day one that this was personal to them and they would not rest until Gerry was found. After all of the communication and information from everyone involved including the Medical Examiner’s Office, Navy, and the Maine Attorney General’s Office, these findings are conclusive in that no foul play was involved and that Gerry simply made a wrong turn shortly after crossing Orbeton Stream. Now that we know her death was an accident, we again ask all media for the respect of our privacy as we continue our grieving process with this new chapter of closure.”

Re-posted from Daily Bulldog: http://www.dailybulldog.com/db/features/missing-at-hiker-died-of-exposure-lack-of-food-and-water/

MWS Press Release from October 16, 2015

[Augusta, Maine – Friday, October 16, 2015]

The Maine Warden Service believes that skeletal remains discovered

in Redington Township are likely those of hiker Geraldine Largay

missing since July 22, 2013. Positive identification will be determined

in the coming weeks by the Medical Examiner’s Office, however, due

to the location of the remains and evidence gathered at the scene the

Maine Warden Service feels confident that Geraldine has now been

located.

The remains were found Wednesday morning October 14 by a

contractor conducting a forestry survey as part of an environmental

impact statement on property owned by the US Navy in Redington

Township. The contractor reported his findings to the Navy who

subsequently alerted the Maine Warden Service. Personnel to include

game wardens, State Police detectives, Naval Criminal Investigative

Service (NCIS) investigators, and a Medical Examiner’s Office

representative hiked to the scene of the remains yesterday morning.

The scene included skeletal remains and several pieces of clothing

and belongings consistent with items known to be in Largay’s

possession. The remains were located west of the Maine Public

Reserve Land that contains a portion of the Appalachian Trail (AT)

and about 3,500 feet east of the easterly shore of Redington Pond

(see accompanying topographic map). The remains will be examined

to determine the cause of death although investigators do not believe

foul play is involved at this time.

These findings will bring closure to one of Maine’s most unique and

challenging search and rescue incidents. Geraldine “Gerry” Anita

Largay, age 66, started her hike on the AT in April of 2013 at Harpers

Ferry, West Virginia; her trail name was “inchworm.” Her destination

was Baxter State Park in Maine. Her husband George kept track of

her along the way and made frequent pre-determined stops to

resupply her.

On the morning of Sunday, July 21, 2013 she departed from her

husband at the Route 4 AT crossing in Sandy River Plantation near

the town of Rangeley. Later that day she texted her husband and

advised she was on top of Saddleback Mountain. Geraldine was last

seen on the early morning of July 22 at Poplar Lean-to on the

Appalachian Trail (AT) in Maine. The attached photo of Geraldine

was taken July 22 at Poplar Lean-to and is the last known photo of

her. She was planning to hike that day to Spaulding Lean-to in

Redington Township, approximately eight miles to the north.

The following day, July 23, she had planned to continue hiking north

from Spaulding Lean-to located in Mount Abram Township to meet

her husband who was waiting for her at the Route 27 crossing.

Geraldine never arrived at that location. Until yesterday, search

efforts yielded no clues that could be attributed to Largay.

The Largay family has asked for time to come to terms with this new

information before making any further public statement, but did want

to express gratitude to all the searchers and investigators who have

taken the time to search for Gerry. The family has been in contact

with Maine Warden Service investigators and has been updated

routinely about searches and investigative leads regarding her

disappearance.

This incident remains under investigation. No further information is

available at this time.

Remains of Geraldine Largay Found!

There is a great deal of excitement, emotion, questions, sadness and relief among the 29 FSAR team members surrounding this announcement. Over the past 2 years, we have not given up searching for Gerry. Members were involved in Largay searches as recently as the past 2 weekends and we have (had) another scheduled for the 25th.

We are all VERY interested in learning the details (today at 1 p.m.) of the location and details of this find.

Hat's off to the entire volunteer SAR community in Maine. What an outstanding group of dedicated and skilled and hard working volunteers that have supported this find that has finally brought closure for the Largay family.

-Mit

+++++++++++++++++++++++++++++++++++++++

[Augusta, Maine – Friday, October 16
NEWS CONFERENCE – Maine Warden Service
Topic: The Maine Warden Service believes that skeletal remains discovered in Redington Township on Wednesday, October 14 are likely that Geraldine Largay, an Appalachian Trail hiker missing since July 22, 2013. Positive identification will be determined in the coming weeks by the Medical Examiner’s Office, however, due to the location of the remains and evidence gathered at the scene the Maine Warden Service feels confident that Geraldine has now been located.
When: 1:00 PM - Friday, October 16, 2015
Contact: Game Warden John MacDonald (Maine Warden Service PIO)
John.macdonald@maine.gov
207-557-0818
Please join us today at 1:00 PM for details. Representatives from the Maine Warden Service and the Navy’s NCIS team will be available for comment and questions. A news release will also be distributed by 2:00 PM this afternoon that will include today’s news conference details. No further information is available at this time.

Wilderness First Aid with Paul Marcolini at KFD

Wilderness First Aid (WFA) Class Is Filling Quickly, Register Soon!

Wilderness First Aid

by: Wilderness Medical Associates

Date: October 3-4, 2015

Location: Kingfield Fire Department, Kingfield, Maine.

Time: 8 a.m. to 5 p.m. Saturday & Sunday

Cost: $199

The best and most comprehensive course of its kind to offer relevant and realistic first-aid training for seasonal outdoor activities or short term wilderness endeavors and pursuits.  Wilderness First Aid is a two-day introduction to general medical concepts and basic life support skills. It is targeted to the outdoor enthusiast on day trips or short adventures. The course is taught by professional instructors with significant patient care and backcountry experience.

Taught by: Wilderness Medical Associates    http://www.wildmed.com/

Sponsored by: Franklin Search & Rescue (FSAR) http://franklinsar.blogspot.com/

Course topics:

Patient Assessment System; CPR; Circulatory System; Nervous System; Respiratory System; Fractures, Stable Injuries; Splints 1-Extremities; Hypothermia; Hyperthermia and Heat Illness; Near Drowning; Lightning Injuries; Wounds and Burns; Anaphylaxis; Lifting, Moving Extrication; Patient Carries; Backcountry Medicine

Certifications

This course is scheduled for two days or 16 hours of instructional and practice time. Upon successful completion students will receive certification in Wilderness First Aid and Adult CPR.

Students will receive the following books on this course:

• Wilderness First Aid Guide
• SOAP Notebook;
• The Outward Bound Wilderness First-Aid Handbook

Evaluation

Successful completion with certification is based on 100% attendance, satisfactory performance on homework assignments and written quizzes, demonstrated proficiency with practical skills, and a successful grade on a final written exam.

Prerequisites

Students must be at least 16 years old to participate in this course. Those under 18 years of age require the written consent of a parent or guardian.

To register:

Contact FSAR team member Melissa Shea:

mountainguideservice@gmail.com

(207) 319-9583

Marsden Trail Search, Baxter State Park, August 29-30, 2015

• 

  Team 3 takes a short break along the Marsden Trail before heading into the thick fir.

• 
  
• 2 FSAR members, Mit and Jimmy A. left Franklin county at 7:30 p.m. Saturday 8-29
• Jim L. planned to join us but had family car troubles
• Arrived at Togue Pond Bunk House 10:30 p.m, pitched bivy bags and were in bed before 11.
• Began day by having breakfast with MESARD in the crew cabin.
• 6 a.m. cut the waiting hiking-vehicle line at Togue gate and drove to the CP arriving at the Marsden trail-head at 7.
• We were assigned a high-priority grid that according to the WMS officer in charge, was  “the ‘toughest, most difficult search area of the day”!
• Our team was lead by BSP ranger Rob and included 2 young MWS wardens and a Dirigo SAR member.  
• “We want to get you guys up there right away, so we are going to use the helicopter”!
• Briefed on helicopter ops by Rob and then had an amazing 4 minute ride (see video here)
• https://www.youtube.com/watch?v=Y4DQsWs7V6M
• Were dropped off on a large rock in Teardrop pond at 2300’ bushwhacked to the Marsden trail from the pond.
• Hiked up to our search area around 3400’
• In Jimmy’s words, “Brutal, bloody, bushwhack through very dense fir”. We traveled 500’ in 45 minutes at one point.
• On completion of our first mission, we searched along the trail back toward the C.P. at the Marsden Trailhead.
• Around 2 p.m, we heard the preliminary and then confirmed radio traffic that Mr. Lyon had been found alive.
• He was found signaling on a rock slide by the same helicopter and pilot that had flown us to Teardrop Pond.
• He was flown to the hospital and where he was admitted for treatment.
• We continued our descent to the C.P. arriving around 3:30.
• After re-hydrating and pigging out on some delicious pizza, we headed for home.
• It was a great adventure with a happy ending.
• Hat’s off the the amazing members of the MWS team, BSP rangers and MASAR teams from all over the state.

Hurry up and wait!

Jimmy made good use of the wait-time in the gravel pit LZ.

Rob gives a helicopter safety briefing.