Marine scientists have been surprised by the persistence of an unusual red tide along the Washington and northern Oregon coast.
This is the algae bloom which produced a slimy foam that killed thousands of seabirds earlier in the fall.
Foam turned up on coastal beaches again on Monday, but the bird die-off has not resumed. Correspondent Tom Banse reports from Ocean Shores, Washington.
Marine biologists and oceanographers continue to puzzle over what triggered the deadly algal boom and whether there's more to come.
University of Washington professor Julia Parrish joined more than a dozen researchers in Ocean Shores to compare notes.
Julia Parrish: "It sort of makes me think about mold in your house. Is it one of those things, once it gets into the bathroom tile, you have a heck of a time getting it out of there."
Parrish estimates more than 10,000 seabirds died in two waves between early September and late October. Basically, the birds got slimed by a foam previously unseen in the Northwest.
It was naturally produced when waves churned decaying algae. The foam matted the feathers of diving birds so they could no longer stay warm.
Julia Parrish says the underlying red tide or algal bloom persists.
Julia Parrish: "We've all declared it over and over and over and it just keeps blooming. It's a bit Friday the 13th."
Marine biologists hope this week's storms churn the ocean waters enough to disperse the deadly algae for now.