November 07, 2012

Seattle Gets Ready for Snow!

The "official" snow season in the Northwest lowlands starts on November 15th and the threat this winter is greater than we expected a few months ago.

During the summer, it looked like this winter would be characterized by a moderate El Nino, but increasingly it appears we will be in a neutral or La Nada year. (El Nino years are associated with tropical Pacific sea surface temperatures above normal, La Nada years--near normal ocean temps).  El Nino years are usually associated with less snow than normal, neutral years bring average amounts.  And the rare big snowstorms are usually in neutral years.
Many of the latest forecasts, including this one from the NOAA Climate Forecast System is going for a weakening El Nino to Neutral Conditions
So the threat is there:  is the City of Seattle prepared?  The bottom line:  the situation has greatly improved during the past few years.

And we should not forget that Seattle is far more vulnerable to snow than its modest median snowfall (around 7-8 inches) would suggest.  The hills make even a light dusting dangerous.  The large number of elevated bridges and roadways freeze up quickly.  Because of our mild climate, snow often melts during the day and then freezes into ice at night.  And yes, our drivers are not as experienced and skilled in dealing with the white stuff as folks back east.   Add to these issues, the difficulty of accurately forecasting snow around here, and you have major problem.

Let me admit that I have strong feelings about this topic.  I still get a visceral shudder when I think back to December 2008 when snow and ice crippled Seattle for two weeks.   My car was trapped at my house since it couldn't get up the hills.   Buses were either non-existent or late.  Major roads were rutted and impassable.  I arrived at Sea Tac from a meeting and couldn't get home.  The UW was closed for days and many Seattle residents and commuters could not get to work.  Hundreds and hundreds of accidents. And of course the singular picture of the bus hanging over the freeway.   The cost of the poor preparation and street maintenance had to be in the hundreds of millions of dollars.  A reflection of a city without the equipment, interest, or know-how to deal with only modest amounts of snow.  It ended the mayoral career of Mayor Nickels. 

This could have been a major tragedy
In contrast, Mayor McGinn's office have taken a very proactive and activist approach to snow preparation and removal in the city (and considering what happened to Mayor Nickels you can't blame him).  He hired an experienced team at Seattle Department of Transportation (SDOT), added plows and equipment, and developed a coordination plan with a variety of agencies (e.g., METRO).   The city now uses chemical pretreatment to prevent ice and snow from binding to roadway surfaces, and salt to melt and loosen up snow/ice after they are in place.  Plows now have metal tips and snow is plowed towards the side of the road. With additional equipment added this year, the city has 40 snow plows, 4 deicer vehicles, 3,800 tons of granular salt and 47,000 gallons anti-icing storage capacity...roughly three times more granular salt storage than last season.

I am really hopefully that METRO will be ready for snow this winter.  First, that they use the GPS-enabled buses to upgrade their bustracker applications so they are effective during snow periods...WHEN THEY ARE MOST NEEDED.  Second, that they don't turn off their bustracker applications at the first sign of snow.   And finally, that they have a plan to put MORE BUSES on major roads given priority clearing by SDOT, using the buses from cancelled routes.  Some folks may have to walk a bit to their apartments or homes, but there is no reason that Metro buses can't keep the city alive even during a major snow event.

No rubber blades here!
That is all well and good.  But as a meteorologist, what gets me really excited is that this year, for the first time, the city will have road temperature sensors at 5-10 locations, some on elevated highways and others on roads in contact with the soil.   It is hard to do an optimal job in preparing for and dealing with a potential or actual snow/ice  if you don't know the temperature of the roadway surface.   Earlier this year, the Mayor's office and the City Council authorized these sensors and most are now installed.  Thus, SDOT will be able to determine whether bridges are starting to ice up and thus get equipment in place, before the road freezes up and the traffic gridlocks (and makes it impossible to get trucks in there to deal with the problem).   During other periods, when roadway are sufficiently warm, SDOT can save thousands of dollars knowing when they don't have to pretreat.

These new road sensor data will be available for all of you to view on the web site my group has built with City support:  SnowWatch (for whom the main developer is UW Meteorologist Jeff Baars).

Here is a view of SNOWWATCH Thursday AM.  The road surface temperatures will be shown surrounded by  a box.  SnowWatch is a sophisticated application that brings in all relevant information regarding Seattle snow, and includes warming capabilities for SDOT personnel.  Next we need a smartphone app for it!

Add to all the above, the new coastal weather radar, better forecast models, GPS navigation on Metro buses, and excellent road ice prevention and removal by Washington DOT for mainline roads, and I am very optimistic.

If only my profession could learn to forecast snow better....

Just a reminder..I will be talking about regional climate change tonight at the Mountaineers in Seattle (7 PM)...more information on the upper right of this blog.


  1. Ah 2008, the year I was diverted to San Jose for a night when coming home from UH for Christmas. What a fun year.

  2. Is there any way that the public might get access to the surface-temperature telemetry data?


  3. I see that the maps are just images right now. Is there any chance you'll release the data behind this too? It wouldn't have to be complex: just the lat and long, timestamp, and temperature. I bet you already have all this data in CSV, XML or JSON and are using it to render the maps.



  4. I see that the maps are just images right now. Is there any chance you'll release the data behind this too? It wouldn't have to be complex: just the lat and long, timestamp, and temperature. I bet you already have all this data in CSV, XML or JSON and are using it to render the maps.



  5. I was looking at the surface temperature data, and there is one sensor that is regularly 5-10 degrees off from the others. It looks to be near UW campus.

    Where exactly is this? Is it just the sensor malfunctioning, or is there really a road that is already freezing?

  6. Cool site, but why do the temps vary 2-4 degrees in such a short (second or less) time span?

  7. Unknown -

    > Cool site, but why do the
    > temps vary 2-4 degrees in
    > such a short (second or
    > less) time span?

    You are seeing a loop of reports over the last six hours or so.

  8. I'm really hoping that "greater threat" materializes! It's been a pretty quiet start to the season so far....Maybe the calm before the storm? Fingers crossed!

  9. I have often wondered by they don't use trained citizen volunteers for things like road temperatures. 3 or 4 neighbors could arrange to cover one spot, and using a code send it in to the city.

    My county refuses to use citizen help to monitor rivers levels, and never are up to date with the Newaukum/Chehalis fork. Several very upstanding citizens in the location could easily ensure the county has good data.

  10. Cliff, is there a way to contact you by email? The email button in your sidebar isn't working correctly.

  11. Hi Cliff, as an engineer I really appreciate the effort and science you put in this blog. AWESOME JOB!
    I have a question though. Where is the SNOW? Snoqualmie pass still doesn't enough snow. Temperatures have been slightly above freezing point.
    Do you expect things to change? When?


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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