Monday, November 29, 2010

November 22nd winter storm response...

By guest bloggers Jeff Switzer and Bronlea Mishler

No one wants to be stuck in the middle of a gridlocked freeway in sub-freezing conditions. We apologize for the frustration and inconvenience that many commuters experienced during the snowstorm Nov. 22. Our goal is to keep the roads clear and traffic moving no matter what the weather throws at us.

On Sunday, Nov. 21, our maintenance crews pre-treated every mile of highway in King County and every on- and off-ramp with liquid anti-icer to keep ice and snow from sticking. When snow fell Monday morning, the majority of the roads remained bare and wet because of the anti-icer, and crews continued treating areas of snow and ice with either a sand/salt mix or liquid deicer.

By Monday afternoon, snowfall intensified and freezing temperatures turned standing water and slush into ice. We had 23 maintenance trucks on the road in the Seattle area treating more than 250 lane miles of freeway as commuters started filling up I-5 early to beat the impending storm. Our maintenance trucks soon got stuck in the backups and behind disabled vehicles and collisions, and that prevented them from continuing to actively salt and deice some roads. Narrow highway shoulders also prevented our trucks from getting around congested areas to continue treating icy areas, like I-5 in Tukwila.

The section of I-5 near Boeing Field and through the Duwamish Curves is elevated, which causes it to freeze more quickly when temperatures drop. There are few on- and off-ramps in this area, so drivers couldn’t exit to city streets to avoid the backups. A serious collision closed all lanes of southbound I-5 at 5:41 p.m. bringing traffic to a standstill. At the same time, the city of Seattle closed SR 99, which funneled more traffic to city streets and I-5. We warned drivers on our electronic signs that southbound I-5 was closed south of the I-90 interchange, and directed them to use I-90 and I-405 to avoid the worst congestion near Boeing Field. The freeway didn’t recover from this and other collisions until past midnight. Here are some photos of freeway conditions that evening.

Storms like the one we experienced this week certainly challenge us all in keeping the system working well. We are carefully analyzing our entire storm response, as we always do, and will make whatever adjustments are needed for the next storm.