Manti-La Sal Avalanche Center

US Forest Service Manti-La Sal National Forest

Introduction:

Good Morning! This is Evan Stevens with the USFS Manti-La Sal Avalanche Center with your avalanche and mountain weather advisory. Today is December 26th, 2003 at 7:30 A.M

General Conditions:

Our technical difficulties have cleared up thanks to some wandering in the mountains in the zero visibility fog and tropical storm force winds. Today should be a transition day, as the snow begins to pile up. This morning, it is a bit like Bermuda during Hurricane season, with temperatures near freezing at the trailhead, 20 at Pre-Laurel Peak, and sustained winds in the mid 30’s from the S with gusts up to 79mph! Look for a variety of snow surfaces out there from hard slab in exposed locations to old settled snow in the trees. We picked up 1 or 2 inches of snow yesterday, so the snow stake still stands at 27” at the Trailhead and 36” in Gold Basin.

Mountain Weather:

A winter storm warning continues through today. Total accumulations should be between 8-16”. Today should see the bulk of that moisture, with highs near 30 and SW winds at 35-45mph. Tonight, snow continues, but the front pushes through, changing the winds to the NW at 10-15mph, with 2-4” of new snow. Tomorrow highs should be in the 20’s with a chance of snow showers and NW winds at 10-20mph. The pattern stays unsettled for a little while.

Avalanche Conditions:

Yesterday was quite an interesting weather day. Most of the day saw cloud line sitting at about 8,000’, which resulted in rime being deposited on many snow and tree surfaces. This was accompanied and followed by about an inch of graupel and moderate winds. Essentially, our snow surface is set up for some interesting action once the snow starts to pile up. Hard slabs were also quite abundant on NW-NE aspects, although only 2-6” deep, as there was minimal snow to transport. The bottom line though is the chance for 8-16” of snow and very strong and sustained winds, which will start from the S and wrap around to the NW, which means many aspects will be loaded. Right now the new snow is only a trace, so the danger continues to be MODERATE at and above treeline on steep slopes with W-N-E aspects. As the day goes on the danger should bump up to CONSIDERABLE in wind loaded areas steeper than 30 degrees, with a MODERATE below treeline on slopes steeper than 35 degrees, as a foot of snow in these areas may be too much for an already weak, shallower lower elevation snowpack. Remember to look for signs of instability such as cracking and collapsing, which will indicate the rising danger!

Nordic and Skate Skiing:

New snow means the skating and Nordic skiing may not be so great today…

Public Announcements:

We still need volunteers and observers! Call us at the office for more info, 259-7155 for more info, or 636-3363 after hours. Get ready for our avalanche awareness courses coming in January. Check the education page for a course near you.

Word of the Day:

Leeward sides: Not knowing this term could make you wonder where the snow would end up during a wind event. There are two areas, the windward and the leeward sides of mountains. The windward side faces where the wind is coming from, the leeward side is the opposite. The wind picks up snow on the windward slopes, also known as “fetch areas”, and deposits them on the leeward side. If the wind is coming from the South, expect Northerly aspects to have wind loading.