Avalanche Advisory

Issued: Thursday, April 6, 2017 7:00 AM
Updated: Thursday, April 6, 2017 7:01 AM
Forecaster: Victor McNeil

Primary Problem

Secondary Problem


BOTTOM LINE:

The Wallowa’s and Elkhorn’s will be affected by a moist southwesterly flow, set to bring moderate to strong winds and up to 1.5’ of snow by Saturday evening. New snow will be falling on a melt freeze crust on all aspects and elevations, up to at least 9,000’. Caution should be assumed on steep terrain >35 degrees, as wind slabs and storm slabs will be touchy with the new snow sitting on the old crust. It can take a couple days for the new snow to securely bond the old crust, so before committing to a steep slope take time to evaluate this interface. Use safe travel protocols, such as skiing or high marking one at a time and choose safe re-grouping areas out of the run out zone.

SPECIAL ANNOUNCEMENT:

As flowers begin to bloom and the grass is in need of mowing, most folks move on from skiing and begin their spring/summer activities. At the avalanche center we want to sincerely thank everyone who helped make this a successful season. Our fund raising efforts were incredible and we feel fortunate to have so many supporters of our avalanche center. Although there is still plenty of snow above 7,000’ and avalanches can and will continue to occur, this will be the FINAL advisory for the spring.

Recent Activity

Yesterday in the Northern Elkhorn’s roller balls were observed on all aspects and elevations up to 8,800’. The past couple days have been quiet warm, with little to no freeze at night to lock up the snowpack. Snowmobilers and Timber Sleds had been high marking between Lee’s Peak and Lake’s Lookout and were not producing any avalanche activity. In the Northern Wallowa’s on Tuesday I was able to see many old wet loose avalanches on Chief Joseph.

Current Conditions

Here’s the weather roundup as of 5:30 AM this morning: Anthony Lakes 33 degrees, SE wind 13 MPH, with gusts in the mid thirties, Mt. Howard 36 degrees, SSW wind 20 MPH with gusts into the upper thirties, Salt Creek Summit 43 degrees, with a S wind of 15 MPH and at the Aneroid Lake Snotel it was 40 degrees. This morning a warm front is passing through and snow levels remain above 7,000’ through today, in the Elkhorn’s and Wallowa’s. A moist southwesterly flow will impact the mountains of NE Oregon through the weekend, with temperatures and snow levels dropping, beginning Friday afternoon. By Sunday morning the Northern Wallowa’s could see around 1.5’ of new snow, while the Elkhorn’s are forecasted to receive 1’. Winds are already blowing moderate to strong, mainly from the SW and will continue into Saturday. Snow levels will drop below 4,000’ Saturday into Sunday and temperatures will hover around freezing for daytime highs, with lows in the 20’s. Temperatures will be below normal into early next week and forecasts are calling for unsettled weather to continue through next Wednesday.


Avalanche Problem #1

ASSESSMENT
By Saturday evening forecasts are calling for snowfall totals of 1.5' in the Northern Wallowa's and 1' in the Elkhorn's. This new snow will be accompanied with moderate to strong winds from the SW building wind slabs on NE aspect. These wind slabs will be sitting on a smooth sliding surface and will likely be reactive to the weight of a skier or rider. Caution should be assumed on wind loaded slopes >35 degrees, until the new snow has a chance to bond to the old snow interface. If you see signs of wind slabs including: shooting cracks, collapsing, chalky snow features and pillows, use caution. Cornices are still hanging on and should be given a wide berth. If you aren't walking on dirt ridgeline or around trees and big rocks, you could be on a portion of the cornice that could fail. Avoid traveling underneath cornices and skiing or riding on slopes with cornices above them.


TREND

Increasing over next 48+ hours
LIKELIHOOD

SIZE

Avalanche Problem #2

ASSESSMENT
Any new snow we receive will be falling on a melt freeze crust on all aspects and elevations up to at least 9,000'. Loose dry avalanches and storm slabs should be expected on steep terrain >35 degrees through Sunday. Use caution as the new snow will need a couple days to bond to the old interface. Travel and ski/ride one at a time on steep terrain and choose safe regrouping areas. Eventually the sun will re-appear and temperatures will rise to above freezing. Solar aspects will see the impacts first as roller balls, pinwheels and wet loose avalanches will begin as the surface snow is warmed. During these typical spring conditions use caution as the surface snow is warmed after a recent snowfall. Once melt water percolates down to old crusts there is a greater chance of wet loose and wet slab avalanches. A good mantra to follow is when the air temperature goes above 32 degrees: go higher in elevation, find a north aspect or just go home, especially when you have wet snow up to your boot tops.
TREND

Increasing over next 48+ hours
LIKELIHOOD

SIZE

Mountain Weather

fwus46 kpdt 251056
 sagpdt
 
 avalanche guidance
 national weather service pendleton or
 356 am pdt sun jun 25 2017
 
 orz050-260100-
 wallowa mountains 8000 to 9000 feet-
 356 am pdt sun jun 25 2017
 
 .today...sunny. light winds. highs 66 to 73. 
 .tonight...clear. light winds becoming south around 10 mph after
 midnight. lows 49 to 56. 
 .monday...partly cloudy in the morning, then mostly cloudy with
 chance of showers and slight chance of thunderstorms in the
 afternoon. southwest winds around 10 mph. highs 61 to 68. 
 .monday night...showers likely and chance of thunderstorms in the
 evening, then slight chance of thunderstorms after midnight.
 northwest winds around 10 mph. lows 38 to 45. 
 .tuesday...partly cloudy in the morning then clearing. west winds
 around 10 mph. highs 50 to 57. 
 .tuesday night...clear. northwest winds around 10 mph in the evening
 becoming light. lows 32 to 39. 
 
 

General Annoucement

This will be the Final Advisory for the spring season.


DISCLAIMER: This advisory does not apply to developed ski areas and avalanche terrain affecting highways.