NWAC avalanche forecasts apply to backcountry avalanche terrain in the Olympics, Washington Cascades and Mt Hood area. These forecasts do not apply to developed ski areas, avalanche terrain affecting highways and higher terrain on the volcanic peaks above the Cascade crest level.
Weekend Outlook for Friday April 29th to Sunday May 1st
Avalanche Forecasts have ended for the 2015 - 2016 season. Weekend Outlooks will be issued Thursdays April 28th and May 5th, 12th, 19th, and 26th. Special advisories, watches, and warnings will be issued throughout the spring for unusual or dangerous avalanche conditions.
April has been somewhat of a roller coaster especially for freezing levels and temperatures.
The last warm, dry period came about April 16th to 21st when freezing levels rose again to around 12,000 feet.
A little more snow was seen about April 22nd to 24th with perhaps 1-2 inches or so at higher elevations along the west slopes of the Washington Cascades and with 2-6 inches at NWAC station at Mt Hood.
A cool period with mostly minor showers has been seen the past few days ending Thursday April 28th.
Recent Snow and Avalanche Observations
Observations are a bit few and far between for the past few days although I know folks have been out skiing.
NWAC observer Dallas Glass was out in the Paradise area on Sunday 4/24 and found about 2 inches of new or storm snow well bonded to previous snow which tended to be unfrozen. There were no signs of wind transport. While this gave a fresh coat of paint to the mountain it was not enough for new avalanche problems. He did not visit the above tree line but felt that there would need to be more wind and snow there to create new avalanche problems.
The North Cascade Mountain Guides were out near Washington Pass on Tuesday 4/26 and found some recent cornice falls that did trigger some small to large loose wet avalanches.
A report on Turns All Year also for Tuesday 4/26 for Black Peak indicated 1-2 inches of new snow and good corn snow conditions.
The DOT crew at Chinook Pass on Wednesday 4/27 reported firm snow and good spring skiing.
Weather, Snow and Avalanche Outlook for Friday to Sunday
Warm periods in April seem to have done a good job of consolidating and stabilizing the upper snowpack in the Olympics, Washington Cascades and at Mt Hood. The mid and lower snowpack should also mainly consist of firm, stable layers of rounded snow crystals and crusts from warm or warm, wet periods this winter.
Light to moderate west-northwest flow will carry a weak front across the Northwest on Friday morning. Short lived convergence may shift south over the central Cascades. This should cause another 1-2 inches of snow along the west slopes above about 5-6000 feet, with less or little at Hurricane and along the east slopes. Light showers along the west slopes should end Friday evening.
The minor amounts of rain or snow mainly along the west slopes and cool temperatures on Friday should not be enough to create significant new avalanche problems. Snow conditions on Friday should remain over mostly firm and stable with minor amounts of new snow along the west slopes above about 5-6000 feet.
An upper ridge and dry warm air mass should build over the US coastal waters on Saturday and Sunday. This will mainly cause northwest winds on Saturday to become northeast on Sunday, and sunny weather with a warming trend Saturday and Sunday. Some offshore surface flow should develop later Sunday. Freezing levels should rise to about the 10,000 foot range later Saturday and Sunday.
Some melting and softening of surface snow on steep solar slopes may be possible by Sunday. Watch for loose wet surface snow deeper than a few inches, pinwheels or rollerballs or initial small loose snow avalanches that precede larger loose snow avalanches. It will probably still be good to avoid areas below gullies and avalanche run out zones especially the ones that are in the sun. But good spring snow conditions and generally safe avalanche conditions should be seen this weekend.
The report above from the North Cascades Mountain Guides indicates it will still be a good plan to avoid areas along ridges or summits that may still have cornices and to avoid slopes below cornices this weekend.
Remember that this forecast is for areas in the Olympics and in the Cascades up to the crest level and does not apply to higher elevations on the volcanoes.
This Outlook will not be updated unless there is a significant change from the expected conditions this weekend.