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What is an avalanche warning?

What is an Avalanche Warning? How to Understand Mountain Safety Alerts

Avalanches, the powerful and often sudden slides of snow down a mountain, pose a significant risk to anyone in mountainous regions during the winter and early spring. When conditions are especially prone to avalanches, local authorities sometimes issue an Avalanche Warning to alert residents and visitors about the ongoing risk. But if you don’t live in a mountainous area, you might be wondering, what exactly is an avalanche warning? What do they mean?

Understanding avalanche warnings is crucial for anyone planning to venture into these areas. This comprehensive guide aims to answer all your questions about avalanche warnings. First, let’s go over some background knowledge about avalanches more generally.





Table of Contents

What is an Avalanche?

An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can occur in any mountainous area where there is an accumulation of snow. They are typically triggered when the weight of the snow, ice, or a combination of these exceeds the strength of the snowpack, causing a sudden and often violent slide.





How Does An Avalanche Happen?

Avalanches are influenced by several factors, including the slope’s steepness, the snowpack’s stability, the weather conditions, and human activity. They can be extremely powerful and pose significant risks to people in the affected area, including the potential for burying, injuring, or killing people caught in their path.

Understanding avalanche safety, including recognizing the signs of potential avalanches and knowing how to respond, is crucial for anyone engaging in winter outdoor activities in mountainous regions.

What Are The Most Common Types of Avalanches?

There are several types of avalanches, including:

  1. Loose Snow Avalanches: These start from a single point and gather snow as they move downhill, typically occurring after fresh snowfall.

  2. Slab Avalanches: These are more dangerous and involve a cohesive slab of snow breaking loose from a weaker layer of snow beneath. They can be triggered naturally or by human activities like skiing or snowmobiling.

  3. Wet Avalanches: These occur when the snowpack becomes saturated with water, often due to melting or rain. They tend to move more slowly but can still be very destructive.

  4. Cornice Fall Avalanches: These happen when a mass of snow and ice overhangs a ridge line and breaks off.

In the continental United States, slab avalanches caused by a weak layer of snow are the most dangerous and deadly type of avalanche, responsible for most accidents and injuries. 

What is An Avalanche Warning?

An avalanche warning is an alert issued by avalanche forecast centers. It indicates that avalanches are very likely to occur and could be widespread. These warnings are based on a detailed analysis of numerous factors, including snowpack stability, recent snowfall, wind, temperature, and terrain.

An avalanche warning is similar to other types of weather warnings, like a Tornado Warning, Severe Thunderstorm Warning, or a Blizzard Warning. The main difference is that an Avalanche Warning lasts several days after a severe weather event like blizzard, until the snow has a chance to stabilize. Most types of warnings occur during the event itself (tornados and severe thunderstorms). 





How is An Avalanche Warning Issued?

Avalanche warnings are typically issued by national or regional avalanche forecast centers. In the United States, for instance, the Colorado Avalanche Information Center (CAIC) and similar organizations in other states play a key role in monitoring conditions and issuing warnings. These centers employ expert forecasters who analyze data from weather stations, perform field observations, and use scientific models to predict avalanche risks.

When an Avalanche Warning is issued, you can find it on an Avalanche Forecast website, social media feeds, and the National Weather Service. You can also follow The Next Summit on social media, as we try to share the latest updates on avalanche warnings and safety conditions.

What is the Difference Between a Warning and an Advisory?

Avalanche warnings and advisories are crucial tools for safety in mountainous, snow-covered areas, but they serve distinct purposes. An avalanche warning is issued when there is a high probability of avalanches, indicating severe and imminent danger. It often advises against travel in avalanche-prone areas and is typically issued for a specific, often short, time frame. In contrast, an avalanche advisory provides ongoing, detailed information about the snowpack’s condition and potential avalanche problems. While it highlights potential risks, it does not necessarily imply an immediate high danger level as a warning does.

Advisories are more educational, assisting backcountry users in making informed decisions and are updated regularly throughout the avalanche season. Understanding the difference between these alerts is essential for making safe choices in winter mountain environments.

Understanding the Avalanche Danger Scale

Avalanche warnings often come with a danger scale rating. In most cases, an Avalanche Warning is issued when the danger reaches an extreme level, usually after a significant snowstorm or blizzard event. The five rating levels include:

  1. Low: Generally safe conditions, watch for unstable snow on isolated terrain.
  2. Moderate: Heightened avalanche conditions on specific terrain features.
  3. Considerable: Dangerous avalanche conditions. Careful snowpack evaluation and cautious route-finding necessary.
  4. High: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
  5. Extreme: Widespread natural or human-triggered avalanches certain.
What is An Avalanche Warning? Danger Scale

What to Do When an Avalanche Warning is Issued

When an Avalanche Warning is issued in your area, you should take extra precaution to ensure you safety, even if you do not plan to enter avalanche terrain. Often, during periods of extreme avalanche danger, slides run in places previously not considered dangerous, destroying homes, roadways, and even ski resorts and lodges. Follow these best practices to give yourself lots of extra margin for risk: 

1. Get the Forecast and Read It

Knowledge is power! Reading the forecast will provide critical information about the current level and type of avalanche danger in the areas you hope to visit. This includes the type of avalanche, the slope aspect and elevation where the danger is highest, what warning signs you should watch for, and other helpful information. Things change constantly, so check back each day during the Avalanche Warning period. 

2. Avoid All Avalanche Terrain

During times of extreme danger, the only sure way to avoid an avalanche is to avoid all avalanche terrain. That means any snow-covered hillside with a slope angle between 30-45 degrees (you may wish to avoid anything above 25 degrees to give yourself an extra margin for risk). Be wary of less steep terrain below or otherwise connected to avalanche terrain, which can still be hit or trigger a slide from afar. 





3. Plan Alternative Routes

If you are committed to making it out to the backcountry despite an Avalanche Warning, have multiple backup plans ready in case you come across surprising conditions that pose an unreasonable level of risk. In a worst case scenario, be ready to turn around and ski back to your car without anything significant to show for your efforts; better to live to ski another day.

4. Travel with An Emergency Kit

Thanks to the hard work of CDOT, it is rare for avalanches to impact highways and roads in Colorado. However, during an Avalanche Warning all bets are off. If you must drive through the mountains during a time of extreme danger, keep an emergency kit in your vehicle at all times. Ensure it includes extra food, water, and blankets, hat and gloves, satellite communication device, first aid kit, fire starters, and a stove.

If your car is hit or buried by an avalanche, stay with/inside your vehicle and wait for help.

5. Stay Home

When there is an Avalanche Warning in effect, the best thing to do (in my risk-adverse opinion) is to stay home and enjoy a Snow Day. Unless you live on a mountain slope below an avalanche chute, it is probably the safest place to be during an Avalanche Warning. When in doubt, stay home. The mountains will still be there tomorrow or next week.

Myths and Misconceptions

There are a lot of myths related to avalanches and our safety. Here are a few common misconceptions related to our answer to the question, ‘what is an avalanche warning?’

 


 

MYTH #1: Avalanches strike at random, often without warning.

FACT: Most fatal avalanches are not random but are triggered by the victim. There are often recognizable warning signs before an avalanche occurs: shooting cracks, recent avalanche activity, and a collapsing ‘wumpf’ sound. Additionally, avalanche forecast centers often issue an avalanche warning specifically to warn that slides are imminent. 

 


 

MYTH #2: You can just outrun an avalanche on skis or a snowmobile.

FACT: An avalanche can reach speeds upwards of 80mph which is far too fast for a skier or snowmobile to outrun.

 


 

MYTH #3: Avalanche forecasts and warnings are overly cautious and overstate the danger level.

FACT: Warnings are based on scientific data and expert analysis and are issued on rare occasions. They should always be taken seriously.





When an Avalanche Warning is Not Issued

No warning doesn’t always mean no risk. Avalanches can still occur in moderate or even low-danger conditions. Always assess the situation independently.

While avalanche warnings provide crucial information, they are not a substitute for personal responsibility. Skiers, snowboarders, and others in backcountry areas need to make informed decisions based on both the avalanche forecast and their observations.

Avalanche Safety Best Practices

Venturing into the backcountry during winter brings the awe of pristine landscapes but also the real danger of avalanches. Whether you’re skiing, snowboarding, hiking, or climbing, adhering to avalanche safety best practices is crucial. Here’s a quick guide to keeping safe:

  • Check Local Avalanche Forecasts: Before any trip, consult the local avalanche forecast and weather conditions.
  • Carry Essential Gear: Always have an avalanche transceiver (beacon), a probe, and a shovel. Know how to use them.
  • Travel with a Partner: Never go alone. Maintain visual or verbal contact with your partner at all times.
  • Learn and Practice Safety Skills: Enroll in avalanche safety courses to understand terrain analysis, snowpack conditions, and rescue techniques.
  • Plan Your Route Wisely: Avoid steep slopes and areas with signs of recent avalanches or unstable snowpack.
  • Stay Alert: Continuously observe your surroundings and be prepared to adjust your plans.


Avalanche safety is about knowledge, preparation, and making informed decisions. For a more in-depth understanding and additional safety tips, we encourage you to visit our comprehensive mountain safety guide. This resource will provide you with the tools and information needed to enjoy the backcountry safely and responsibly.

avalanche danger colorado

What is An Avalanche Warning? Now You Know!

Understanding avalanche warnings is a matter of safety and responsibility in the backcountry. By respecting warnings and staying informed, outdoor enthusiasts can significantly reduce their risk of encountering a dangerous situation.

Stay Safe and Informed!

For the latest updates and information on avalanche warnings, you can visit National Avalanche Center or your local avalanche forecast center’s website. Remember, the mountains are a beautiful but unforgiving environment. Respect them and stay safe.





FAQs

If we haven’t addressed your burning question already, leave a comment and we will get back to you with more info and an answer as soon as possible.

Q: What is an avalanche warning?

A: An avalanche warning is an alert issued by avalanche forecast centers indicating a high probability of avalanches in a specific area. It suggests that both natural and human-triggered avalanches are very likely under current conditions. This warning is based on detailed analysis of the snowpack, weather, and terrain.

A: The avalanche danger rating is a standardized scale used to communicate the level of avalanche risk. It ranges from Low, Moderate, Considerable, High, to Extreme. Each level reflects the likelihood of avalanches and the potential size and distribution of avalanches within the forecasted area.

A: During an avalanche warning, it’s crucial to:

  • Avoid avalanche-prone areas, particularly steep slopes.
  • Follow updates from local avalanche centers.
  • Postpone or reroute your backcountry plans.
  • Carry and know how to use avalanche safety gear (beacon, shovel, probe).
  • Stay alert and cautious if you must be in potential avalanche zones.

A: Predicting the exact occurrence of an avalanche is difficult, but there are signs of potential instability:

  • Recent avalanche activity in the area.
  • Cracking or “whumping” sounds in the snowpack.
  • Rapid temperature increases.
  • Heavy snowfall or rain in a short period.
  • Visible snowpack layering or weak layers.

A: Avalanche prediction involves analyzing several factors:

  • Snowpack stability assessments.
  • Weather forecasts and recent weather history.
  • Terrain analysis.
  • Historical data and patterns of avalanche occurrence.
  • Observations from professionals and recreationists in the field.

A: To stay safe in an avalanche:

  • Carry avalanche safety equipment (beacon, shovel, probe).
  • Stay to the side of slopes and avoid the path of potential avalanches.
  • If caught, try to move to the side, grab onto something sturdy.
  • Once stopped, create an air pocket and attempt to push a hand above the surface.

A: There are sometimes certain warning signs before an avalanche, but not always. Immediate warning signs before an avalanche can include:

  • Audible cracking or “whumping”.
  • Ground vibrations.
  • Rapid weather changes. However, these signs are not always present or noticeable, emphasizing the importance of proactive safety measures and avalanche forecasts.

A: If your car is covered by an avalanche:

  • Stay inside the vehicle. It offers protection and a larger air pocket.
  • Turn off the engine to avoid carbon monoxide buildup.
  • Try to clear an airway through a window or door if possible.
  • Use a car horn or alarm to attract rescue attention.
  • Remain calm and conserve energy while waiting for help.




Additional Reading:

Check out these additional websites, articles, and resources to continue learning about avalanches. They all can help you answer the question, ‘What is an avalanche warning?’ If you know of additional resources to share, please mention them in a comment so we can add them to the list.









Alex Derr, Founder of The Next Summit

Alex Derr is an Eagle Scout, climber, and environmental policy expert located in Denver, Colorado. He created The Next Summit to help others stay safe exploring the mountains and advocate to preserve the peaks for the future. Follow him on Linkedin or Twitter or click here to contact him.





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