Weather Blog

How much snow fell, and how windy is it?

How much snow fell, and how windy is it?

 With gusty winds and mountain snow in the minds of all this week, I've got two good resources to answer those two burning questions in the headline.

First up, the easy one -- how windy is it?

There is a great map from the National Weather Service that shows just about every observation site you can think of -- some are official sites like airports and the like, but others are part of the MesoWest network. Those are a series of private and other government agencies that maintain a weather station and transmit data to the National Weather Service.

Here is the wide map of Western Washington

And some zoomed in maps of North Puget Sound region and Central/Southern Puget Sound Region

You can hover over each spot on the map to get a quick synopsis of the weather, or click on the name in the table below to get a time series.

The only trick here that I've noticed is that these sites do not report a peak hourly gust, which I find quite valuable during wind storms. For example, it'll report the gust around the time of the observation, but they do not show the top gusts of the hour. To find those, you have to do some digging as they are only reported in the "Remarks" field of the hourly observation.

To find those, I use this University of Washington site. Now, if you just got eager and clicked on that link, you're probably going "Whoa! That's really cryptic!". But here is the key: The station codes are on the left, and there is a link at the top of that page that takes you to a list of those location codes.

The current wind is under "SP" column with current gust under "GS" (these are in knots, which are 1.15 mph). But to find the peak gust, you have to look all the way over on the right in the remarks code.

Look for the code "PK WND" which means "Peak Wind". The numbers that follow are coded to show direction of peak wind gust, and when it was recorded. The first three numbers are compass direction; second two numbers are speed and the number after the slash is the time the gust was recorded in GMT.

So if one said: "PK WND 26028/2004" that means a peak gust of 28 knots was recorded from 260 degrees (west) at 20:04 GMT. GMT is 7 hours ahead of Pacific Daylight Time and 8 hours head of Pacific Standard Time, so this time of year on Daylight time, 20:04 GMT means 13:04 PDT -- or 1:04 p.m.

OK, so it's windy down here. How much snow fell in the mountains?

You can always just check the ski resort pages, but they are usually only updated once or twice a day.

But for current snow totals, I use this this site form the Northwest Avalanche Center. If you look on the left, there is a table of observation sites up in the mountains. But in true weather geek tradition, these are somewhat coded too.

Here is an example of one of the readings, from Mt. Baker:

You want to look under the "24 Hr Snow Total" column, which shows snow totals, but here's the catch: The total is accumulative, and then it starts over. I've found that when the gauge is reset is somewhat variable.

So in this example, it starts at 4" then climbs to 17", then resets to 0 at 5 a.m., then climbs back to up 5". The way I would read this is that 13" of snow fell between 2 p.m. on April 7 and 4 a.m. on April 8. (It's 13" since it was 4" at the start and rose to 17" meaning 13" fell in that time period.). Then another 5" fell between 5 a.m. and noon.

Thus, you could present it as 18" of new snow since Wednesday morning, or 5"of snow since Thursday morning.

But again, take these numbers with a grain of salt. Computers don't do the best job of measuring snow, and typically when it is snowing up there, the weather is quite miserable, so it can affect the readings. And to top it off, sometimes it's got errors, so use it as a general guide. There will also be times where the number seems to get lower, as in 3" as of 5 a.m. but 2" as of 7 a.m.. It's possible the snow compressed or melted. (I see this drop occur on Snoqualmie Pass' site a lot).

But it's something besides taking a long drive up there in a snow with a ruler to get your own measurement :)