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THIS AVALANCHE ADVISORY EXPIRED ON April 2, 2019 @ 6:26 amAvalanche Advisory published on April 1, 2019 @ 6:26 am
Issued by
George Halcom - Payette Avalanche Center
bottom line
The Avalanche Hazard is Low Today. Use caution in or around wind-loaded, steep terrain. Shallow wind slabs with poor bonds exist in upper elevations. Wet-loose avalanche possibility will linger in the lower elevations today, and will be on the rise tomorrow as warm temperatures persist.
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Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Loose Wet
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Character ?
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Aspect/Elevation ?
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Likelihood ?CertainVery LikelyLikelyPossible
Unlikely -
Size ?HistoricVery LargeLargeSmall
Today, your best chance of kicking loose a wet loose slide would be on very steep lower elevation slopes. We have seen a fair number of loose wet slides over the last few days. The last round of snow went through a few days of melt freeze cycles which gave the upper snow pack strength until about noon. Over the next few days, lower elevations are not going to be getting a solid freeze overnight, so expect the snow to become increasingly soft, especially Tuesday with Rain on snow up to 6-7,000 feet where the likely hood of wet slides will increase.
Avalanche Problem 2: Wind Slab
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Character ?
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Aspect/Elevation ?
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Likelihood ?CertainVery LikelyLikelyPossible
Unlikely
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Size ?HistoricVery LargeLargeSmall
Upper elevations have remained cooler, and have a dusting of new snow on the surface that fell as recent as yesterday. Shallow wind slabs with poor bonds exist, but we have not seen any activity over the last week. Mit pits showed shallow slabs around 2 inches thick on the surface that are not bonded well, but are staying put, and supporting weight right now. The mountains picked up around 12 inches with some gusty 30 MPH winds last week, and its a good idea to remember the variability that comes with Spring, and that the snow fell on Sun and rain crusts that had formed prior to the storm.
advisory discussion
PAC will issue 3 Advisories per week through April 5.
Your Observations are extremely helpful and appreciated by all backcountry users. If you have not checked our our Observations page, it is really easy to add snow or avalanche info. Drop down menus and prompts will lead you through it and it is easy to add photos.
Please be aware that there are areas that are CLOSED to motorized traffic in the McCall, Goose Lake and greater West Mountains area. Just because there are tracks in some areas, does not mean they are open. Please respect all users and closures. See the Payette Winter Travel Maps for clarification. Both the East and West maps can be downloaded on the Avenza app on your phone or are available at trailheads and local shops. IT IS YOUR RESPONSIBILITY TO KNOW WHERE YOU ARE AND WHERE THESE CLOSURES EXIST.
recent observations
Yesterday, we toured The Grassy Mountains just North of Granite Mountain. The snow pack was starting to soften around 10am, but increasing clouds kept things a little cooler and even put down snow at times. Upper elevation pits and mit pits revealed shallow wind slabs around 2 inches thick on the surface that are not bonded well, but are staying put, and supporting weight. Wet loose debris from the Sun was observed in many East and South Aspects. While skiing steep South chutes that feed into Hard creek, we were only able to get a very small wet slide to initiate with a ski cut and run about 6 feet. Below 7,000 feet the snow is really melting and creeks are opening up.
Wet loose slides from the Sun below the rocks on South faces of Grassy Mountains
old debris in one of the SE facing Chutes that feed into Hard Creek
Hard creek is going off, and is loud right now...be careful near creeks.
CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
| 0600 temperature: | 28 deg. F. |
| Max. temperature in the last 24 hours: | 32 deg. F. |
| Average wind direction during the last 24 hours: | SE |
| Average wind speed during the last 24 hours: | 5 mph |
| Maximum wind gust in the last 24 hours: | 18 mph |
| New snowfall in the last 24 hours: | NA inches |
| Total snow depth: | NA inches |
weather
Area Forecast Discussion
National Weather Service Boise ID
256 AM MDT Mon Apr 1 2019
.SHORT TERM...Today through Thursday...An area of low pressure off
the Pacific coast will influence weather over the next couple of
days. The northwest flow over the area today continues to escort
moisture towards eastern Oregon, with showers expected this
morning. Showers look to spread into southwestern Idaho by the
early evening hours. Models continue to show some instability
across eastern Oregon this afternoon, with a slight chance of
thunderstorms included. As the area of low pressure moves inland
on Tuesday, showers will remain over the area, with snow levels up
to around 6000-7000 ft. The organization of the low falters on
Tuesday, with the system converting to a wave. As this trough
axis moves through the area, expect improving conditions for
Wednesday, with mainly a few lingering mountain showers. The next
approaching system moves into the Pacific Northwest on Thursday
morning, with showers possible Thursday afternoon across the area.
Temperatures will cool in response to the initial system on
Tuesday, with a return of a warming trend on Wednesday and
Thursday. Overall, temperatures remain within 5 degrees of normal
through the period.
.LONG TERM...Thursday night through Sunday...The progressive
pattern will continue with Pacific weather systems bringing
showery periods. Temperatures will average around 5 degrees above
normal. Moist southwest flow ahead of a deep upper level trough
centered off the northwest coast will provide isolated showers for
the valleys and more numerous showers over the mountains Thursday
night and Friday. Showers will become widespread Friday night and
continue through Saturday as the trough moves inland. Another
upper level trough, centered in the Gulf of Alaska, will spread
showers inland as far south as northern Nevada Saturday night
through Sunday night. Precipitation chances will decrease on
Monday as weak high pressure builds over the Intermountain Region.
Snow levels will be between 6000 and 7000 feet.
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.AVIATION...VFR today. Precipitation spreading into eastern Oregon
this afternoon and central and southwest Idaho tonight, with areas
of low VFR/MVFR ceilings and mountain obscuration. Snow levels 6500-
7500 ft MSL. Surface winds light and variable becoming east to
southeast through the Snake River Valley this afternoon. Winds aloft
at 10k ft MSL southwest to west 10-20 kts.
Two-Day Mountain Weather Forecast
Produced in partnership with the NOAA-NWS
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Disclaimer
This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.