Powerful storms to unleash torrential rain and dangerous, potentially deadly waves across Pacific Northwest

The latest atmospheric river is currently scraping western Washington, bringing rain to the Olympic Peninsula and Washington Cascades.

THE TAKEAWAY: 

  • Strong atmosphere rivers continue to impact the Pacific Northwest with heavy rain, gusty winds and snow.
  • Over the weekend, the storm will intensify, triggering wind gusts that could reach 50 to 60 mph along the coast.
  • Massive 20 to 25 foot waves and offshore seas exceeding 30 feet are expected to slam the shoreline.
  • "The large wave runup may dislodge logs on area beaches and result in them rolling up and down area beaches, which have historically killed or seriously injured unsuspecting people," the NWS said.

Powerful atmospheric rivers continue to target the Pacific Northwest this week, bringing rounds of heavy rain, strong winds and snow to higher elevations.

WHAT IS AN ATMOSPHERIC RIVER?

But the greatest threat may be along the coastline, where massive ocean swells are expected to generate destructive surf and life-threatening sneaker waves.

Sneaker waves are hazardous waves that can surpass normal surf activity and become deadly and destructive.

The latest atmospheric river is currently scraping western Washington, bringing rain to the Olympic Peninsula and Washington Cascades.

Conditions along the Oregon and Washington coasts have been hazardous all week, with 15- to 20-foot westerly swells dominating the waters.

These long-period swells can generate sudden sneaker waves that surge significantly farther up beaches than normal, sweeping over rocks and jetties with enough force to roll heavy drift logs.

"Destructive waves may wash over beaches, jetties, and other structures unexpectedly," the National Weather Service (NWS) said. "Extreme caution should be used if you plan to visit beaches this week."

The combination of high astronomical tides and persistent onshore wave energy is also expected to produce minor tidal overflow and significant beach erosion. 

High Surf Advisories are now in place along the Washington coast.

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However, according to FOX Weather, this event is relatively minor compared to the more powerful system expected to arrive over the weekend.

Beginning Friday, a stronger storm system will push a pair of fronts onshore, bringing soaking rain and gusty winds. 

Wind gusts could reach 50 to 60 mph along the coast and 40 mph across the Interstate 5 corridor.

WHEN IS THE EARLIEST SNOWFALL ON RECORD FOR PARTS OF THE NORTHEAST?

Colder air is expected to arrive late Sunday into Monday, dropping snow levels to around 3,500 to 4,000 feet and bringing another round of snow to the Cascade passes.

Along the coast, massive 20- to 25-foot waves and offshore seas exceeding 30 feet are expected to slam the shoreline.

These conditions could produce destructive, crashing surf capable of surging over coastal structures and temporarily submerging beaches.

"The large wave runup may dislodge logs on area beaches and result in them rolling up and down area beaches, which have historically killed or seriously injured unsuspecting people, so there will be much more of a threat than just getting wet from a rogue wave," the NWS said.

The series of storms expected over the weekend is part of a larger weather pattern that will cause atmospheric pressure to drop between systems. In some cases, pressure is forecast to fall as low as 950 to 960 millibars.

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These powerful low-pressure systems will help generate even stronger winds over the Pacific, fueling massive ocean swells that will push toward the coastline.