US Forest Service Manti-La Sal National Forest

Snow, Weather and Avalanche Advisory

 Introduction:

This is Max Forgensi with the USFS Manti-La Sal Avalanche Center with your with your avalanche and mountain weather advisory for the Wasatch Plateau/Manti Skyline Region, including, but not limited to Ephraim, Huntington and Fairview Canyons. This advisory is brought to you through a partnership of Utah State Parks and the USFS. Today is Sunday, February 20th, 2005 at 7:30 am.

Current Conditions:

It appears that the meat of the storm missed us yesterday, the split flow went around the Manti-Skyline. For today, buried sun crusts and cornice development is what’s on tap…there is plenty of snow on everyone’s favorite designated trails and powder fields. Unfortunately, the Mammoth/Cottonwood SNOTEL stake stopped working yesterday at 4:00 p.m, giving us no exact snow totals or current temperatures. Hopefully it will be fully operational sometime today. There will be increased traffic on the Skyline for President’s Weekend, please drive defensively and park courteously.

Mammoth/Cottonwood SNOTEL: At least 50” of snow on the ground.

Miller Flat Trailhead: There is at least 54” of snow on the ground.

Mountain Weather:

Well the storm has finally organized, although it is more stable than expected, which is limiting snow fall for the area.

Sunday: Morning snow then changing to afternoon snow showers. 1-4” of snow could be expected. Highs at 8,000’ will be in the lower 30”s.

Sunday night: Snow. Chance of measurable precipitation is 70%. Winds will be out of the west at 16 mph. Low near 13. Accumulations of 1-2” expected.

President’s Day: 70% chance of snow. Winds will be out of the South at 13 mph. High near 26.

Avalanche Conditions:

There are two concepts one must think about before heading out on the Skyline today, the current hazard and the potential hazard. The storm that rolled through last weekend left a very dense (moist) layer of snow overlying a less dense layer of snow. The strength of the current snow pack was strong enough to stay on the slopes and produce few if any natural avalanches in the past week. It was under a precarious balance that if given the proper trigger, a snowmobile for example, might fail. We had two snowmobile triggered avalanches on the Skyline this past week on North-East slopes. Why isn’t there many natural avalanches? Well, the snow on the ground is waiting for an adequate stress to be applied to it. Will the current storm will tip the scales? There will be strong winds coming in from the South and west, distributing new snow onto the leeward slopes on North through East aspects. Expect cornices to be tender and crack farther back than expected and wind-loading on these slopes that could fail.

The Bottom Line is an avalanche danger of CONSIDERABLE on steep slopes on North through East aspects and around recently deposited cornices. For the rest of the Skyline, I am going to rate the avalanche danger at MODERATE. Keep your slope angles today below 30 degrees, and work on those snowmobile tricks out in the meadows!