Avalanche!!!! The Weather Variable 

The first significant contributing factor is weather.  80% of avalanches occur during or shortly after a storm.  For this reason, the information gathering process must begin BEFORE you leave on your outing.

Before you leave home, gather as much information as possible!  Utilize your local avalanche forecast center's web site and/or recorded avalanche hot line and listen to weather reports on the TV and radio.  The local Ski Patrol may also have information regarding the latest avalanche forecast.

Invest in a commercially sold cross-country trail map if one exists for the area you plan to visit.  Sometimes, dangerous avalanche zones are noted, giving you advance warning of problem areas.

What should you look for when on the trail?  Beware of changing weather patterns, especially unusual changes in wind, snowfall and temperatures.

Storms 
The first thing to look for is storms.  Remember that 80% of avalanches occur during or shortly after a storm, often because of the fact that the existing snowpack cannot support the weight of the new snow, especially if stressed by the added weight of a skier or snowmobiler.

Winds 
You must also be alert to the presence of winds.  Winds of over 15 M.P.H. cause avalanche hazard to increase greatly.  Under these conditions, the wind lifts snow from windward slopes and redeposits it onto leeward slopes.  This produces greater accumulations of heavier, denser snow on these leeward slopes, which stresses the existing snowpack.  Snow plumes off the tops of ridges are a good indication that wind is moving the snow.  Cornices on leeward slopes indicate accumulations of wind-deposited snow.

New Snow 
Snow falling at a rate of one inch per hour or greater increases the avalanche danger as a result of the increased weight.  If a foot or more of fresh snow is deposited at one time, then avalanche danger is often extreme.  Even four inches of fresh snow is dangerous, in conditions of high wind.

Temperature 
Snow remains unstable (or may become less stable) in cold temperatures, due to the temperature difference between the surface of the snow and the surface of the ground.  Once temperatures climb into the range of
20-32 degrees, the snow cover will rapidly stabilize, due to settling.  Temperatures above freezing produce very dangerous conditions, because melting snow introduces water into the snowpack.

Water 
weakens the existing snow crystals and acts as a lubricant in the snowpack.  In other words, temperatures significantly above freezing increase the danger

In our next few posts we will continue to discuss the three main variables that help develop a potentially unstable snowcover: weather, terrain and snowpack. By understanding these variables, backcountry users will have a better chance of predicting avalanche danger.

For more information on avalanche safety check out the Mountain Rescue Associations public education program @ http://mra.org/images/stories/training/Avalanche.pdf as well as our Backcountry Skiing & Riding Safety Video  

Courage - Commitment - Compassion
     Mountain Rescue Association 

The "Average" Avalanche

Avalanches come in all shapes and sizes.  The average snow avalanche is 2 to 3 feet deep at the fracture line, about 150 feet wide and will fall about 400 feet in elevation.  That's a slide area bigger than a football field!  What's more impressive is that the average avalanche travels at speeds around 50 M.P.H., a little faster than most of us like to ski!  The average time duration of a slide of this size is less than 30 seconds.  This is the size of avalanche that catches and kills most backcountry travelers.

Avalanches can be much larger...some of the largest reported avalanches have involved complete mountainsides of snow, the area of 20 football fields, having a depth of 10 feet at the fracture line and falling over 1½ miles at speeds well over 100 miles per hour!  As impressive as these avalanches are, generally the smaller ones are the killers.  In fact, 50% of avalanche fatalities are killed in slides of less than 100 feet and people have been killed in slides of less than 40 feet.  The bigger ones almost always release from natural causes and do not involve people unless they happen to be in the wrong place at the wrong time. Artificial triggers, such as snowmobiles or skiers are much more effective at releasing small to medium sized avalanches in shallower snowpack, where the stress caused by their weight is enough to cause the snowpack to fail.

Avalanches are a powerful phenomenon.  In 1969 at a ski hill in Washington, steel chair-lift poles were bent in an avalanche.  In a recent Colorado avalanche, a flashlight inside a glove compartment of a buried automobile was found completely packed with snow.  Larger avalanches possess the force to uproot mature forests and even destroy structures built of concrete. The reason, forces in excess of 15,000 lbs. per square foot.

The fastest recorded avalanche occurred in Japan and was measured to be traveling at speeds in excess of 230 m.p.h.

Avalanches come in two distinctly different types...  “Loose Snow” and “Slab”avalanches.

Loose snow avalanches are a cohesionless mass of snow that start at a point and fan out as they run, forming an inverted "V".  This type of avalanche usually involves small amounts of near-surface snow and is not considered a major threat to people.  Do not lose respect for these slides as they have taken lives.

Slab avalanches, on the other hand, start when a large area of cohesive snow fails and slides down the slope.  There is a well defined fracture line from where the snow broke away.  In addition, there may be angular blocks or chunks of snow in the slide, sometimes larger than a refrigerator.   A slab avalanche can involve a range of snow thickness from just near surface layers to an event that includes the entire snow cover down to the ground.

Slab avalanches are almost always caused by additional stress on the hill, such as a snowmobiler or skier. Since slab avalanches cause nearly all avalanche accidents, it is important to understand the conditions within the snowpack that lead to these slab avalanches

Snowstorms and wind-redistribution cause the snowpack to develop in layers. Once a layer has achieved sufficient cohesive strength, the first prerequisite for a slab avalanche has been established.  Weather will help add the second requirement...  a weak layer.  If a weak layer has developed underneath a strong layer, the perfect recipe for an avalanche exists.  If the weak layer fails, the cohesive strong layer above it will fracture and fall away from the stress. Both ingredients - a cohesive layer of snow and a weak layer below - are necessary for a slab avalanche.

When the strong layer fractures, the crack is estimated to shoot across the snowfield at a speed of over 1000 miles per hour.

In our next few posts we will discuss the three main variables that help develop a potentially unstable snowcover:  weather, terrain and snowpack. By understanding these variables, backcountry users will have a better chance of predicting avalanche danger.

For more information on avalanche safety check out the Mountain Rescue Associations public education program @ http://mra.org/images/stories/training/Avalanche.pdf as well as our Backcountry Skiing & Riding Safety Video  

Courage - Commitment - Compassion
     Mountain Rescue Association 

AVALANCHE!!! 


Avalanches are a natural phenomenon.  They have been recorded as far back as 192 BC, when Hannibal crossed the Alps.  At one time, it was thought that avalanches were caused by evil witches living in the villages below.  These witches were often burned at the stake after a destructive avalanche. 


The whole key to avalanches is gravity.  Without gravity, there would be no avalanches.  Every flake of snow and every piece of rock has but one wish...  to succumb to gravity and fall to a lower point. It has been estimated that 1 million avalanches occur worldwide each year.  Most of these occur in the Alps in Austria, Switzerland, France and Italy.  In the United States, 100,000 occur annually. 
  
The worst recorded avalanche in the U.S. occurred in 1910 in Wellington, Washington and left 96 dead with 22 survivors.  The worst known in the world occurred in Yungay, Peru and left 20,000 dead.  This avalanche was measured to be 10 miles long, 1 mile wide, and displaced 3 million cubic yards of snow.  3 million cubic yards of snow...  That's enough snow to fill a 200 story building the size of a football field. 


More than 180 people are caught in avalanches each year in the United States.  Of these, 90 are partly or completely buried, 29 are injured and an average of 28 are killed.  Over 200 people die worldwide each year.  These statistics are based on reported burials...  it is safe to assume that many more burials occur than are actually reported. 


From 1950 to 2001, avalanches in the United States killed 491 people. Recreationalists accounted for the vast majority of avalanche fatalities, with climbers, ski tourers, lift skiers, and snowmachiners comprising most of the recreational deaths. The majority of the lift skiers were killed while skiing out of bounds or in closed sections of the ski area. 100,000 avalanches occur each year in the United States.


When looking at avalanche fatalities, one cannot overstate the importance of the human element. In fact, 90% of the time, avalanche victims are killed in avalanches that they themselves trigger.  In other words, the avalanche would not have occurred if they had not been on the slope at that moment. 


Finally, statistics say that 61% of all avalanche deaths occur during the months of January, February and March. 


Over the next few weeks the MRA Blog will go deeper into the science behind what has been appropriately called "White Death." 

For more information on avalanche safety check out the Mountain Rescue Associations public education program @ http://mra.org/images/stories/training/Avalanche.pdf as well as our Backcountry Skiing & Riding Safety Video  

Courage - Commitment - Compassion
     Mountain Rescue Association 

Situational Awareness in Mountain Rescue Operations - Projection into the Future

The third stage of situational awareness – projection into the future – is the stage where one puts it all together.  Once the clues are interpreted, the next step is to project how that information will affect the future of the operation.

Let’s use an example of a traditional backcountry search.  Rescuers are called to a local trailhead to search for a subject who is 6 hours overdue from a planned hike.  The subject told the reporting party (his wife) that he was going fishing at a local lake on the trail.  While some rescuers are searching the trail to the lake, other rescuers also search the subject’s car, and find that his fishing equipment is still in the back seat, including his fishing license.  Using this new information, the rescuers conclude that they need to expand their search area based on the projection that the man changed his plans, and did not go fishing at the lake as expected.

An Everyday Example of Situational Awareness 
Let’s consider another example of situational awareness, one that takes place in an everyday setting.

If you want to know if it is going to rain, you don’t look for rain, you look for CLOUDS.  If you look for rain you’ll only know that rain is coming at the very moment that it arrives. Looking for rain alone would mean that you are only OBSERVING and INTERPRETING, but not PROJECTING into the future.

If, on the other hand, you instead look for clouds, then you have added PROJECTING into your situational awareness.  In that case, you are more able to anticipate rain BEFORE it arrives.

Still, even looking for clouds does not constitute the only important element that is missing if you only look for rain.  You need some training to know WHAT TYPES of clouds cause rain.  For example, a sudden build up of high cirrus clouds means something completely different than a steady accumulation of cumulonimbus clouds.  Only through training and experience can you learn this important distinction.

Visualize While En Route to a Call 
In many emergency medical training programs, students are taught the value of visualizing the scenario prior to arriving at the rescue call.  In search and rescue operations, rescuers often have an extended period of time traveling to the scene of the SAR call.  During that transport time, it can be valuable to take the clues given (e.g. the description of the rescue accident) and project into the future what kind of problems will be encountered by the rescue team.  For example, a rescuer may know that a rescue of an injured climber on the
east side of Highway 9 means that the rescue team will need to create a technical system to cross above a large creek.  While en route to the call, rescuers will already be planning in their heads the tyrolean system
necessary for the creek crossing.

Similarly, SAR field teams can talk about their pending rescue while heading into the field.  On a recent rescue of a survivor from an avalanche, rescuers were performing a technical lowering of the patient to a rock band where the helicopter could “hover load” the patient.  During that technical lowering, the helicopter crew members were sitting in their helicopter at the trailhead parking lot.  The rotors were turning, and the crew was discussing in great detail how they would do the “hot-load” of the subject.  They could have been discussing the latest basketball game, or the lovely weather, but instead they used the opportunity to brief each other on what their duties would be, and on what possible complications might occur.

Experience teaches rescuers to ANTICIPATE possible scenarios based on information provided.  Still, that same experience teaches rescuers that the information provided may be wrong.  While at work one day, an out-of-breath co-worker ran into my office and said, “Charley do you know CPR?”  I followed the co-worker to the hallway, where another staff member was lying on the ground, seemingly lifeless.  Prior to starting CPR, I checked my colleague for a pulse, and asked bystanders what happened.  They described the patient as having experienced what sounded to me like a Grand Mal seizure.  Indeed the patient was in a Post Ictal state, and was not in need of CPR.

For more information on situational awareness in mountain rescue operations, check out the Mountain Rescue Associations public education programs @ http://mra.org/images/stories/docs/sitawareness.pdf

Courage - Commitment - Compassion
     Mountain Rescue Association 

Situational Awareness in Mountain Rescue Operations - Stage II -  Comprehension and  Interpretation of the  Relevant Information 


The second stage of Situational Awareness, “comprehension and interpretation,” requires you to have and utilize your training and experience.  Training is a key component of teaching SAR workers, but experience is the key to understanding how to best utilize that training. 


The second stage of Situational Awareness is the stage wherein one attempts to comprehend and interpret the data collected in the first stage.  While the collection of data and the perception of the relevant information are important, the comprehension and interpretation of that data can not be overlooked. The key to this stage of Situational Awareness is that it requires one to have and utilize key training and experience.  For example, a rescuer in a high mountain rescue might have already perceived that the temperature is very hot.  Still, without proper training in helicopter management, that rescuer he might not be able to interpret that the high temperatures will have an effect on the rescue team’s use of helicopter resources – since temperature has a significant effect on helicopter performance at altitude.  Without the proper training, a SAR worker might not be aware of the limitation that temperature has on the performance of helicopter assets. 


Experience is also a key factor in this stage of Situational Awareness.  While training is essential for any SAR professional, there is no substitute for experience.  It is through experience that we learn and master the  important skills associated with interpreting data that is presented in the first stage of situational awareness. 


Understanding the Clues 
In order to interpret clues, you must first understand them.  But how do you interpret clues if those clues do not make sense?  On a search for a missing hiker one summer night, a rescue professional notified the search command post that he’d found “a bunch of orange pails” in the middle of a trail while searching.  The searcher went on to say that the pails were meticulously laid out in the shape of an arrow, pointing down the trail.   The Incident Command team struggled to figure out why there would be orange pails many miles back on a remote backcountry trail.  Several minutes later, the command team asked for a clarification from the rescuer, who coincidently was a southerner with a deep southern drawl in his voice.  He was asked, “What kind of orange pails are these?”  The man replied “You know, the kind of pails you pail off an orange before you eat it!”  The man was talking about orange PEELS, but that only became evident after the command team asked more questions.  The data presented did not make sense at first, but made complete sense later, once the command team remembered that the field rescuer was from Georgia, and had a distinct southern drawl. 


Interpreting the Clues Requires Training 
Do you have sufficient experience to interpret the information that you have assembled?  Traditional training might not teach you the skills necessary.  For example, one search and rescue team trains its members on helicopter skills in a unique and different way… the rescuers are not schooled in how to help a helicopter pilot, rather they are schooled in how to BE a helicopter pilot by learning how a pilot actually FLIES a helicopter.  As such, these SAR professionals are better able to think like a pilot. 


Recognizing the Frequency of those Clues 
As mentioned earlier, one should not only pay attention to the clues themselves, but also to the frequency of clues.  This can help a rescuer ascertain whether numerous seemingly inconsequential anomalies are coming together to draw one large problem.


Stay tuned to our blog for the continuation of our discussion on Situational Awareness with Stage 3 Projection into the Future. 


For more information on situational awareness in mountain rescue operations, check out the Mountain Rescue Associations public education programs @ http://mra.org/images/stories/docs/sitawareness.pdf

Courage - Commitment - Compassion
     Mountain Rescue Association 

Situational Awareness in Mountain Rescue Operations Stage 1 - Perception of the Relevant Information

Situational Awareness in Mountain Rescue Operations Stage 1 - Perception of the Relevant Information

Yogi Berra once said, “You can observe a lot by just watching.”  Observation is the key to perception.  


In this first step of situational awareness, we are looking for clues.  These clues can come in many forms, including: 
• Sensory clues - something you see, hear, smell, touch; 
• Anticipated clues - something that comes from prior experience; and 
• Innate clues – something you just “feel in your gut.” 


In conventional search missions, for example, rescuers are looking for CLUES more than they are looking for the missing subject.  Why?  Simply because there are far more clues than there are missing subjects, and by finding and following clues, one can find the missing subject much more quickly. 


The first stage of situational awareness – perception – is arguably the most important stage.  After all, without perception of information, one cannot really comprehend, interpret and draw conclusions. Many accidents in search and rescue operations result from a series of different things happening.  There are often a number of contributing factors that, if occurring individually, might not have resulted in an accident.  Break any rescue accident down, and you will often find that there were a number of elements that came together to make that accident possible. 


In this important perception stage of Situational Awareness, rescuers need to be very attentive – not only to the occurrence of situations that are beyond their expectations, but to the frequency and number of those situations. This perception stage requires that you OBSERVE!  In order to be an effective observer, one must remain attentive.  This can be one of the greatest challenges to a search and rescue professional, as periods of  inactivity and boredom can hamper one’s ability to be an effective observer. Similarly, searchers and/or rescuers who are overworked might not be able to observe the environment around them.  This too can be a serious detriment to one’s ability to be an effective observer. 


Stay tuned to our blog for the continuation of our discussion on Situational Awareness with Stage 2 Comprehension and Interpretation of the Relevant Information.


For more information on situational awareness in mountain rescue operations, check out the Mountain Rescue Associations public education programs @ http://mra.org/images/stories/docs/sitawareness.pdf

Courage - Commitment - Compassion
     Mountain Rescue Association 

Situational Awareness in Mountain Rescue Operations

“Situational Awareness” is “the degree of accuracy by which one’s perception of his/her current environment mirrors reality.”  The essence of Situational Awareness is fairly simple… perception vs. reality.

For over 30 years, Situational Awareness has been studied and applied in military, civil, commercial and aerospace applications.  More and more, emergency service organizations are focusing on situational wareness as a key factor in reducing risk and increasing safety. Situational Awareness can also be looked at as a constantly evolving picture of the state of the environment.  It is the perception and comprehension of the relevant elements in an incident within a volume of time and space.  In this regard, Situational Awareness is not an event, but rather a process that only ends when the SAR incident is concluded. Data collection and interpretation.

Situational Awareness requires the human operator to quickly detect, integrate and interpret data gathered from the environment.  In the case of search and rescue operations, the “human detector" can be anything from the Incident Commander to a “field grunt.”  That is the beauty (and challenge) of situational awareness – it requires and demands awareness by all users.

In a search and rescue response, the “information” that is collected can come in many forms, including:
1. Information provided by outside sources (e.g. interviews with reporting parties, information provided by local law enforcement, etc.)
2. Information from the environment (e.g. weather)
3. Information from previous experiences (e.g. other SAR missions in the same location)

Situational awareness is also much like the Incident Command System (ICS), in that it is flexible and should grow or shrink as the SAR incident grows or shrinks.

To fully understand Situational Awareness, we need to look closely at its three important stages, the perception of the relevant information, the comprehension and interpretation of that information, and  the projection of their states into the future.

Over the next few weeks the MRA Blog will examine each of these stages in detail.


For more information on situational awareness in mountain rescue operations, check out the Mountain Rescue Associations public education programs @ http://mra.org/images/stories/docs/sitawareness.pdf

Courage - Commitment - Compassion
     Mountain Rescue Association