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Big rain in the forecast; you can prevent clogged street drains


Storm DrainSEATTLE
— There’s an atmospheric river, aka a Pineapple Express, in the forecast and Take Winter by Storm is urging residents of Western Washington urban areas to adopt local street drains, to make sure they are free of leaves and debris.

When the fall monsoon hits this time of year, storm drains can easily become overwhelmed with leaves and the summer’s accumulated street debris, resulting in backed up gutters and drains, and localized flooding. In Seattle, for example, there are about 80,000 storm drains — far more than city crews can clear quickly.

Safely adopting a local storm drain or drainage ditch — that means staying out of the road when raking — by keeping it clear of leaves, snow and other debris is the single most important thing that residents, businesses can do to protect their property.

James Rufo-Hill, a Seattle Public Utilities (SPU) meteorologist, said atmospheric rivers (ARs) are relatively narrow bands of concentrated moisture that originate near tropical regions and extend into mid-latitude regions such as the Pacific Northwest. Around the planet, ARs come in many different shapes and sizes but those that impact Western Washington are most often associated with powerful low pressure systems, or extratropical cyclones, that move across the North Pacific. Western Washington’s ARs also tend to originate from the vicinity of Hawaii, which is the reason for their “pineapple express” nickname.

“Like snowflakes, no two AR’s in Western Washington are alike,” Rufo-Hill said. “Depending on the orientation of the incoming moisture bands, the region can experience anything from a persistent rainfall and flooding to partly sunny skies. Generally speaking across Central Puget Sound, the more westerly the winds high above the region, the drier it remains; conversely, the more southerly, the wetter.

“It’s during the latter scenario that the region’s drainage infrastructure is put to the test, which is why it’s important that when a “pineapple express” is in the forecast, residents work with their local drainage utility to clean storm drains and report flooding concerns,” Rufo-Hill said.

In Seattle, 90 employees and 60 vehicles are dedicated to maintenance and storm responses. So far this year, city workers have inspected nearly 27,000 drainage basins (there are typically two street drains per basin) and cleaned approximately 30 percent of them. Crews have also cleaned approximately 320 miles of sewer mains.

In addition to adopting a neighborhood storm drain, residents and businesses can take two other important steps to get ready for the storm season:

  • Maintain gutters, downspouts, rain barrels, private culverts by keeping them clean, flowing and directed away from properties and hillsides.
  • Know the emergency hotline number for your local drainage utility, to report sewer backups, major flooding and landslide issues. Take Winter by Storm is a one-stop emergency preparedness center that includes safety tips and regional resources for information about the weather, power outages, flooding, shelters and assistance agencies. In Seattle, that number for reporting flooding issues is 386-1800.

For a wealth of information on preparing for bad weather, visit Take Winter by Storm.