The Avy Report: Late February brings variable snow conditions

Later in a winter season, wet sluff and slides become more of an issue. [Photo] Buri Gyu

Later in a winter season, wet sluff and slides become more of an issue. | Mt. Sandan-yama, Japan| [Photo] Buri Gyu

Earlier this year, we reported on a trend across the western United States of a depth hoar layer that, for many regions and avalanche forecasting centers, was a cause for concern. A month later, the primary concern for avalanches has shifted to a focus on ones of the wetter variety in many locations.

Both the Crested Butte Avalanche Center (CBAC) and the Utah Avalanche Center (UAC) warn of warming during the day that could cause wet slides. In Crested Butte, a wet slide was recorded in the Paradise Divide area on January 17. The CBAC also warns of lurking slab slide potential, and cautions that even though much terrain has been given a low danger designation, backcountry travelers must not let their guard down.

“Persistent slab structures capable of producing large slab avalanches still exist on shadier aspects, but these have trended towards very stubborn to unreactive during our past 2 weeks of mild and dry weather,” explains the CBAC.

In the Ogden and Logan regions of the Wasatch Mountains, there has been a rain-on-snow event that is creating certain pockets of considerable avalanche danger.

“Dangerous avalanche conditions exist today on rain saturated slopes at lower and mid elevations, and people should continue to stay off of and out from under steep slopes with soft and saturated snow,” says the UAC.

Aside from the possibility of wet-slab avalanches, there is also a concern in the Wastach region for slides on wind-loaded slopes near and above treeline in most places and in some, below treeline.

The Northwest Avalanche Center (NWAC) reports that there is a possibility of wet slides, but that a new storm slab that will be building mid-week has the potential to move to the forefront of avalanche hazard concern.

“The avalanche danger should increase rapidly Thursday afternoon and evening due to building wind and storm slab,” says the NWAC. “A cooling trend Wednesday night and Thursday should limit the loose wet problem to below treeline but wet snow hazards will continue.”

The Gallatin National Forest Avalanche Center is a hold out for older avalanche issues that have been plaguing the snowpack all season. Windslab, buried surface hoar and that pesky layer of depth hoar remain an issue in these regions. Rain has reached lower elevations in the Bridger areas as well, however, and so a concern for wet slides does exist in certain areas under the Gallatin National Forest Avalanche Cenenter’s forecasting purview.

The bottom line is that this overview of forecasts from around the western United States shows a regionalism in avalanche issues. This means that to be informed about backcountry travel, make sure you know the season’s avalanche history of the area you wish to explore and stay up on daily forecasts from your local avalanche center before heading out into the backcountry.

For a full report on U.S. avalanches, visit the Colorado Avalanche Information Center website and your regional avalanche forecasting service.

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