Can we talk about how wonderful spring in the Eastern Sierra is? Down here at the Eastern Sierra Interpretive Associations headquarters in Bishop, birds are chirping, trees are blossoming, and warm temperatures mean t-shirts and flip flops once again. But up high in the mountains, it still feels like winter, with fun skiing conditions and beautiful views.  

Just because the roads up into the mountains will soon be opening doesn’t mean that we’re in the clear for avalanche danger, though. And these are not just tips for skiers and snowboarders: hikers, snowmobilers, and snowshoers could inadvertently find themselves in avalanche terrain. Even if trail you’re traveling isn’t steep, you may be surrounded by slopes that carry avalanche danger for those beneath them. This week, we partnered with the Eastern Sierra Avalanche Center to give you a few tips for spring backcountry travel.  

In the spring, as days become longer and that California sunshine radiates onto the mountains, the most prominent avalanche-related concern is what avalanche experts call loose wet avalanches. These avalanches typically begin in a singular spot where the top layer of snow has warmed significantly and become disconnected from subsequent layers of snow. This bit of snow starts to slide and gains more snow as it travels downhill. Though loose wet avalanches may move more slowly than other types of avalanches, the wet snow is heavy and can produce considerable damage to things in its path.  

So how do you avoid loose wet avalanches? Eastern Sierra Avalanche Center Education Coordinator Mike Phillips says to especially consider two things: aspect and timing. When avalanche experts talk about the aspect of a particular slope, they’re referring to the direction it faces. To determine a slope’s aspect, position your back to the slope and measure the direction straight in front of you. Many smart phones have built-in compass apps, and these are perfect tools for determining aspect 

You’ve probably heard that the sun rises in the east and sets in the west, and this is a great catchphrase to remember when considering how snow might respond to sunlight. Any slope that receives abundant sun will be a likely target for a loose wet avalanche. East-facing slopes will get the first light of the day, making them the first to warm up and soften the snowTemperatures continue to rise as the sun angle increases throughout the southern sky during the day. And finally, the sun hits west-facing aspects in the warmest part of the day, right before it sets, making these slopes of high concern as well.  

Avalanche centers like ESAC use diagrams like this one to demonstrate risk levels on different aspects and at different elevations.

But as with many things in life, timing is everything. Traveling on or near shadier aspects in the morning might reduce your loose wet avalanche hazard, but firm, frozen snow presents other concerns. Springtime in the Sierra often means below-freezing temperatures at night despite warm afternoons, and so morning travel can prove difficult if navigating impenetrable snow. Carrying crampons and an ice axe and knowing how to use them to travel efficiently and self-arrest, if necessary, may very well be life-saving decisions. Mike Phillips of the ESAC recommends tracking conditions throughout the day to see how the sun is affecting the snow. If you’re finding yourself in soft snow, sinking up to the tops of your ski or hiking boots, loose wet avalanche concerns should be in the front of your mind. Also keep an eye out for other signs of unstable snow such as pinwheels or balls of snow rolling down steep slopes. Rapidly rising temperatures and near or above freezing temperatures overnight could be a red flag for increasing avalanche danger as well. 

Spring is a very dynamic season for mountain environments. While loose wet avalanches are one problem, it’s not uncommon to see new snowfall and high winds late into the spring. These changing weather patterns can change dramatically from day to day. But, as the Eastern Sierra Avalanche Center points out, education is key. Taking an avalanche education course is the first step for people who recreate in the snowy backcountry, whether you’re traveling by ski, snowboard, snowshoe, or snowmobile.  Taking a course with a local guide company and checking out the free virtual resources that ESAC and the Bridgepoint Avalanche Center provide is a great place to start, but nothing beats mentorship and time spent in the mountains with experienced people. ESAC is hosting their final FREE virtual avalanche education event of the season on 4/7/21 at 6 p.m. which will share information about spring avalanche considerations and travel advice. 


For more information: 

Eastern Sierra Avalanche Center

Bridgeport Avalanche Center

Snow Travel: Skills for Climbing, Hiking, and Moving Across Snow

The Log of a Snow Survey

The Avalanche Handbook