Avalanche Forecast
Jan 13th, 2019–Jan 14th, 2019
Alpine
2:
Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1:
Low
The avalanche danger rating at treeline will be low
Below Treeline
1:
Low
The avalanche danger rating below treeline will be low
Alpine
2:
Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1:
Low
The avalanche danger rating at treeline will be low
Below Treeline
1:
Low
The avalanche danger rating below treeline will be low
Regions: Mt Hood.
The bottom line: The avalanche danger continues to decrease but once again, loose wet avalanches are possible on steep, rocky and sunny slopes. Avoid terrain traps where even a small loose wet avalanche could cause injury. You may also find lingering wind slabs on steep unsupported slopes hiding out at higher elevations.
Regional Synopsis
January 10, 2019
We’re about a month into our avalanche forecasting season, and what a wild month it has been. We’ve seen the snowpack grow from near non-existent to over a 100 inches deep at Mt Baker. We’ve seen avalanche warnings blanket our coverage area, had several widespread large natural avalanche cycles, and seen persistent weak layers plague nearly every zone. While the active weather pattern has been a welcomed sight, it’s hard to catch your breath.
It looks like this weekend, and extending into next week, we are entering a calm period in the weather. High pressure over Idaho and Montana will keep Pacific storms at bay for at least the short term. As we enter this period of nice weather, there are a few things on our mind here at the avalanche center.
Old Persistent Weak Layers
A high elevation rain event on January 3rd did us a favor in many locations. Besides heavily stressing old weaklayers, the rain created a very strong met-freeze crust, making it extremely difficult to trigger deep avalanches.
There are a few exceptions, and they can be found mainly in the eastern forecast zones. The East-North zone around the Methow Valley and WA Pass did not experience significant rain above 5500 ft, potentially leaving some older weak layers in tact. Areas further east including, but not limited to, Icicle Creek and the Wenatchee Mountains did not receive enough rain to form a strong thick crust. In all of these area, older persistent weak layers are still suspect.
Higher Elevations and Remote Trailheads
Stormy weather over the last month has been keeping most of us closer to common trailheads and recreating at near and below treeline. With nice weather on tap, some of you may be thinking about heading into higher elevation terrain and exploring around more remote trailheads. If you are heading out, take time to consider a few key pieces of information.
At higher elevations the snowpack is very deep and wintery. This stands in stark contrast to the lack of snow at lower elevations. The snowpack you’ve seen on previous outings this winter, doesn’t represent what you will encounter at higher elevations.
We have not received much information about the above treeline nor remote location snowpacks. That means we have a high degree of uncertainty in these areas.
You will need to make observations as you travel to confirm if the avalanche forecast is applicable the the area where you are traveling. When observations lineup with the information in a forecast, its valid. If you see observations that don’t lineup, it’s time to take a step-back.
If you are heading into our regions highest alpine terrain, remember, NWAC forecast apply to areas below the main Cascade crest, or about 8000 ft. So, if you plan to travel to higher elevations on Mt Baker, Mt Shuksan, Mt Rainier, Mt Hood, or similar areas, you will need the skills and information to evaluate the terrain and snowpack.
If you’re heading into higher elevation terrain, remember we don’t have much information about these snowpacks, and therefore have a higher degree of uncertainty. Photo: SimonTrautman
We’d like to thank our NWAC Community for all the wonderful public observation this year. If you are heading out into the mountains, we appreciate you taking the time to let us know what you saw. This is a great way to contribute to the creation of your avalanche forecast. You can submit observations here.
Enjoy the sunshine!
We’re about a month into our avalanche forecasting season, and what a wild month it has been. We’ve seen the snowpack grow from near non-existent to over a 100 inches deep at Mt Baker. We’ve seen avalanche warnings blanket our coverage area, had several widespread large natural avalanche cycles, and seen persistent weak layers plague nearly every zone. While the active weather pattern has been a welcomed sight, it’s hard to catch your breath.
It looks like this weekend, and extending into next week, we are entering a calm period in the weather. High pressure over Idaho and Montana will keep Pacific storms at bay for at least the short term. As we enter this period of nice weather, there are a few things on our mind here at the avalanche center.
Old Persistent Weak Layers
A high elevation rain event on January 3rd did us a favor in many locations. Besides heavily stressing old weaklayers, the rain created a very strong met-freeze crust, making it extremely difficult to trigger deep avalanches.
There are a few exceptions, and they can be found mainly in the eastern forecast zones. The East-North zone around the Methow Valley and WA Pass did not experience significant rain above 5500 ft, potentially leaving some older weak layers in tact. Areas further east including, but not limited to, Icicle Creek and the Wenatchee Mountains did not receive enough rain to form a strong thick crust. In all of these area, older persistent weak layers are still suspect.
Higher Elevations and Remote Trailheads
Stormy weather over the last month has been keeping most of us closer to common trailheads and recreating at near and below treeline. With nice weather on tap, some of you may be thinking about heading into higher elevation terrain and exploring around more remote trailheads. If you are heading out, take time to consider a few key pieces of information.
At higher elevations the snowpack is very deep and wintery. This stands in stark contrast to the lack of snow at lower elevations. The snowpack you’ve seen on previous outings this winter, doesn’t represent what you will encounter at higher elevations.
We have not received much information about the above treeline nor remote location snowpacks. That means we have a high degree of uncertainty in these areas.
You will need to make observations as you travel to confirm if the avalanche forecast is applicable the the area where you are traveling. When observations lineup with the information in a forecast, its valid. If you see observations that don’t lineup, it’s time to take a step-back.
If you are heading into our regions highest alpine terrain, remember, NWAC forecast apply to areas below the main Cascade crest, or about 8000 ft. So, if you plan to travel to higher elevations on Mt Baker, Mt Shuksan, Mt Rainier, Mt Hood, or similar areas, you will need the skills and information to evaluate the terrain and snowpack.
If you’re heading into higher elevation terrain, remember we don’t have much information about these snowpacks, and therefore have a higher degree of uncertainty. Photo: SimonTrautman
We’d like to thank our NWAC Community for all the wonderful public observation this year. If you are heading out into the mountains, we appreciate you taking the time to let us know what you saw. This is a great way to contribute to the creation of your avalanche forecast. You can submit observations here.
Enjoy the sunshine!
Weather Forecast
Weather Synopsis for Monday night through Wednesday
Strong upper-level high pressure is centered over the Intermountain West, extending across the Pacific Northwest. This pattern is blocking Pacific storms and providing fair weather along with unseasonably high freezing levels.
A low-pressure system is centered near the central California coast on Monday afternoon.
Freezing levels remain near 10,000 ft Monday afternoon with several NWAC stations reaching the 50's in areas away from the cooling effects of the easterly winds.
Low-level offshore flow is maintaining strong temperatures inversions with sub-freezing temperatures in the passes and lower elevations east of the crest.
The upper ridge will maintain dry conditions through Tuesday before some moisture begins to lift northward across the area late Tuesday.
Freezing levels will lower Tuesday and high clouds begin spreading northward Tuesday afternoon as the ridge begins weakening.
The low-pressure system currently off the California coast weakens and lifts northward Tuesday night and Wednesday, spreading light precipitation over the area at lowering freezing levels. The initial precipitation should remain light and generally favor the volcanoes.
Avalanche Problems
Loose Wet
With sunny skies and mild temperatures forecast again on Monday, loose wet avalanches are most likely to release from steep, rocky, sunny slopes as the day progresses. Monitor changes in the upper snowpack, looking for natural pinwheels or small loose wet avalanches as clear signs of increasing danger. Avoid terrain traps like gullies where even a small avalanche can bury you.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1
Wind Slabs
You may still find and trigger older wind slabs on steep unsupported slopes at higher elevations. Due to variable winds in the Mt. Hood area last week, wind slabs may exist on a variety of aspects. Feeling for firm or hollow sounding snow provides clues that you may trigger a wind slab avalanche on nearby steep slopes.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely
Expected Size: 1 - 1