Avalanche Advisory
Advisory: Skyline Area Mountains Issued by Brett Kobernik for Thursday - March 5, 2015 - 7:05am
bottom line

Dangerous avalanche conditions exist in the upper elevation more northerly terrain where large avalanches are likely to be triggered by people. Avoid the higher more northerly facing terrain. It would be wise to let the steep east facing slopes settle for another day as well. Wet avalanche activity may also happen today with the sun heating the new snow on the sunny aspects. Get off of steep slopes as they become wet and don't linger below or in gullies.
special announcement

Due to dangerous avalanche conditions, we are updating the advisory during the week this week. This advisory will be valid through Friday and we'll update again Saturday morning.
current conditions

The two feet plus of new snow that the Manti Skyline received is starting to settle but dangerous avalanche conditions exist. This is something we are not used to as of late. Travel was fairly difficult through the deep snow but it will become easier as more settlement occurs. We noticed a difference between yesterday morning and yesterday evening. Skies have cleared out and ridgetop temperatures are in the low teens with light northwest winds.
recent activity

There were a number of natural avalanches that occurred during the storm Monday and Tuesday and I suspect we'll find more as we travel around more. There were also a couple of human triggered avalanches on Wednesday. At least one of these broke into old weak faceted (sugary) snow and was fairly large. This is a dangerous situation as more of these could be triggered over the next few days.

Date Region Place Trigger Depth Width Aspect Elevation Weakness
03/4/2015 Skyline Skyline Summit Snowmobiler 3' 150 Northeast 10000 New Snow/Old Snow Interface Details
03/4/2015 Skyline Spring City Canyon Skier 2.5' 250 Northeast 10300 Facets Details

This slide was most likely snowmobile triggered This was a skier triggered avalanche breaking into old facets
Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

By far, the most dangerous situation is in the upper elevation northerly facing terrain where old weak snow is now capped off with 2 to 3 feet of new snow. Human triggered avalanches will be likely through this weekend in the higher terrain. Slopes that avalanched in December are especially suspect as they have a VERY shallow and weak snowpack. This is a dangerous situation because people can travel on a lot of different slopes without triggering anything or seeing any obvious signs of instability. This may give people a false sense of security and then decide to get onto more northerly facing terrain. Make no mistake that this a bad deal.
Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

The newest snow on it's own is stabilizing and it will become less likely that someone triggers an avalanche that breaks just within the new snow. However, with direct sun today, the new snow may become damp and unstable. It is hard to predict when wet avalanche activity will occur but there are a couple of factors in place that point to dangerous conditions. First, a bunch of fresh snow and second, direct springtime sun on the new snow. With quite a bit of new snow, wet avalanches could be fairly large if they start happening. Stay off of and out from underneath steep sunny slopes as they heat up and become damp.

weather

It looks like a nice day out there today with mostly clear skies, ridgetop temperatures into the upper 20s or low 30s and light to moderate northwest wind. The direct sun will make things feel warmer. We should see nice weather into the weekend with gradually warming temperatures.
general announcements

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The information in this advisory is from the US Forest Service which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.

This advisory will be updated by 7:00 AM Saturday, March 7, 2015 or sooner if conditions warrant.