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A resilient ridge (more on that later) has built over the Pacific West coast. This is maintaining unseasonally warm air and dry conditions from California right up to Vancouver Island and deep into the BC interior. Locally we are sitting in a South/South Westerly flow at the top of this ridge.
Locally this means unseasonally warm conditions, with moderate to strong winds. BUT while the unseasonably warm temperatures across the territory have some lamenting (or celebrating) the end of winter before Christmas, the ridge may actually be a blessing in disguise for us Northerners. Multiple storms and low pressure events in the Aleutian gulf are blocked from their usual southerly path, and instead channeled right into our backyard:
So, for the forecast (from now until Wednesday): Expect moderate southerly winds, peaking Monday morning, unsettled conditions, with a brief break overnight into Tuesday and light precipitation. Temperatures will cool over the forecast period. White Pass may see quite intense precipitation with up to 20cm of snow over the coming days.
At Mt Sima (1180m) 0700, 081217, We had broken skies, moderate southerly winds and 0 precipitation. We received 0 snow in the last 24hrs, with very light rain briefly yesterday morning. Temperature was +2.1 with 45% Humidity. Pressure was 1008 Mb with a falling barometer.
Ski hill open this weekend, and conditions yesterday were fantastic. Particularly given our absence of snow anywhere else, come spin some laps!
Have a great weekend! Steve
The weather isn’t super interesting at the moment: It was COLD, then it warmed up, it’s going to go back to being cold for a day or two, then very warm (like + temps.). We’ll get a bit of precip. but not much. That being said, do you wanna hear about Surface Hoar? I know I do…
Last night built some really spectacular surface hoar on open aspects at 1180m:
Erm, lovely, so what does that mean?
Well, surface hoar is fancy words for frost. It sure is pretty. But what is it, and why is it important? Well, here’s the nerd stuff on Surface Hoar. But, if you can’t be bothered with that, here’s the ‘Cole’s notes’ (TM):
Surface Hoar forms on cool, clear, humid (relatively), calm nights by water vapour condensing on the surface of the snow. It generally needs clear skies (i.e. not in forested areas, no cloud cover) to form. And it builds these beautiful feather or wedge like structures on the surface of the snow.
But should you care? It depends. Surface Hoar is not a problem. Until it is a problem. On its own, Surface Hoar is pretty benign. But, if conditions remain calm until more precipitation falls, the new snow will layer on top of those pointy Surface Hoar structures. Spatial variability is key - in one area, Hoar may not have developed, in another, it may have been knocked down by wind, but, in a third, it may have grown and then seen layered snow on top. Herein lies the problem: The Hoar layer will support the snow (think about putting playing cards on end and then stacking a baking sheet on top of them). However, impart a force laterally to this baking sheet (snow) (like a skier or whatever…) and the Hoar layer may collapse, like the playing cards in the analogy. And like this…
Depending on a number of factors, buried Surface Hoar can become a persistent weak layer in a snowpack, that is difficult to detect, and may linger for a long time. Ever heard a ‘whumpf’ when travelling on snow? That could have been a buried Hoar layer collapsing.
Argh! Now I’m scared!
Right? Well, don’t panic just yet… Instead, if you’re travelling in the mountains in the next few days, look for this pesky beast. Where is it? Where isn’t it? Get those MIN reports in here. Even if you’re out walking the dog in town, take a look at spots where Surface Hoar grows fast (besides creeks is a classic), so you can better identify it in the backcountry. And let’s see what the next weather system gives us.
At Mt Sima (1180m) 1200, 011217, We had clear skies, calm winds and 0 precipitation. We received 0 precipitation in the last 24hrs. Temperature was -9 with 79% Humidity. Pressure was 1006.5Mb with a rising barometer.
Have a great weekend! Steve
Well, the charts say one thing, the forecast says another… Low pressure in the gulf of Alaska will see cloudy skies, unsettled conditions and light precipitation prevail through the day
Where it gets interesting is Sunday:
Which I think looks like: Clearing skies, SW winds. The forecasts seem to think N winds and continous cloud cover. Who will win!?
Currently it is -19 at the airport (77% RH), under an overcast cloud deck, with light Northwesterly winds.
As predicted the last system deposited snow across our region, and was accompanied by good transport winds. Widespread scouring in ‘fetch’ areas and pressed, wind affected snow in ‘lee’ terrain was observed at treeline yesterday. If you are venturing out into the mountains this weekend keep that in mind. Caution should certainly be excercised on lee aspects (broadly SE in this storm, but be aware that local terrain features may change that). Quick windslab definition here.
Well, it’s still cold. Which is better news than what’s about to happen down south:
An ‘atmospheric river’ has taken aim at the BC/WA coast. They can expect record breaking temperatures and up to a foot of rain! With 3000m freezing levels.
Up here we will continue to see frigid temps and light precip. but, heck, at least we don’t have to worry about flooding.
Expect clearing skies and no precipitation for today. It’ll remain cold. From Wednesday onwards we maybe start seeing some more interesting weather - the 500mb suggests unsettled conditions for the passes and even town:
But looking at the ‘Precipitable Water’ for the same period is less optimistic:
This confused picture is reflected in the weather model precipitation amounts. In summary: