Backcountry users have been eager to hit the slopes with sunny skies and fresh powder, but officials with the Utah Avalanche Center warn of considerable danger for the foreseeable future.
The center issued a special avalanche bulletin on Saturday urging users, in Northern Utah, that a serious avalanche would likely occur over the weekend and over the coming weeks as inconsistent storms overwhelm Utah’s snowpack.
With virtually no snow for a 40-day span, the dry weather in January and February caused a weak base layer of snow to take shape in the mountains, particularly on the shadier, northern-facing slopes. When scattered snowfall in March began burying the persistent base layer between 2 and 4 feet, a slab — which is a strong layer of snow on top of a weak base — formed.
The combination of sugary snow, which has large grains that form weak connections, and new snow on slopes steeper than 30 degrees are the necessary components for an avalanche to occur, according to Trent Meisenheimer, a Utah Avalanche Center forecaster.
Meisenheimer said that the first snowfall started an active avalanche period across the state. Natural avalanches are less likely as the snow begins to stabilize throughout the season, but the risk of avalanches set off by winter recreationists remains the same. Avalanches that occur under the current conditions will be between 2 to 4 feet deep and well over 100 feet wide.
“The slopes are just waiting to be triggered,” he said. “They get a lot of use and we’re fearful that people are going to get stuck.”
Meisenheimer expects the environment will remain the same through the rest of the week, with heightened or dangerous conditions. The avalanche forecast rating is determined by a danger scale that considers five risk levels from low to extreme. “Considerable” is the third-highest risk level, behind “high” and “extreme.”
Avalanches are less likely to occur during prolonged periods of dry weather but new snowfall can cause the danger to increase if the persistent weak layer remains. Over time, there’s a lower avalanche risk if the base layer is healed through various levels of snowfall and sunshine, but Meisenheimer said it’s hard to know if that will happen before the end of the season.
As the problems persist, officials warn users to remain vigilant and not to overlook the risks of an avalanche. Last winter, there were six fatalities in the backcountry in Utah with another death close by in southeast Idaho, making it one of the deadliest winters in the state’s history.
There have been no fatalities this year but a Morgan man was rescued in Summit County after being buried near Whitney Reservoir on March 7. The Utah Avalanche Center reports there have been more than 30 avalanches in the Salt Lake and Uinta regions over the past week. As of Tuesday morning, there is considerable risk of avalanches in the central Wasatch Range, which includes the Park City ridgeline, and the Uintas — as well as much of the state.
“We’re stuck with that weak layer for a while,” Meisenheimer said. “It’s important to remember the consequences (of an avalanche regardless of the danger rating) are the same. You’re playing a deadly game.”
Users are encouraged to pay attention to the avalanche forecast, which is updated every day, to receive travel advice and danger ratings. They should also plan to carry the right equipment like shovels and probes when traveling into the backcountry.
The avalanche forecast and additional information can be found at the Utah Avalanche Center website, utahavalanchecenter.org.