'Bomb cyclone' brings high winds and soaking rain to U.S.

What was expected to be one of the strongest storms in the northwest U.S. in decades arrived Tuesday evening, knocking out power and downing trees across the region.

The Weather Prediction Center issued excessive rainfall risks as the strongest atmospheric river that California and the Pacific Northwest has seen this season bears down on the region. The storm system is considered a "bomb cyclone," which occurs when a cyclone intensifies rapidly.

The areas that could see particularly severe rainfall will likely reach from the south of Portland, Oregon, to the north of the San Francisco area.

Hurricane-force winds, which are gusts above 120 kph, could be felt along the Oregon coast. And near Seattle, conditions for a "mountain wave" were shaping up, bringing large, low elevation wind gusts that could cause widespread power outages and downed trees.

More than 106,000 customers had lost power in Washington as of Tuesday evening, according to poweroutage.us. More than 11,000 had lost power in Oregon and nearly 12,000 in California.

In northern California, flood and high wind watches were in effect, with up to 20 centimeters of rain predicted for parts of the San Francisco Bay Area, North Coast and Sacramento Valley.

A winter storm watch was issued for the northern Sierra Nevada above 1,000 meters, where 28 centimeters of snow was possible over two days. Wind gusts could top 120 kph in mountain areas, forecasters said.

(Cover: A 'bomb cyclone' rotates off the U.S. west coast on November 19, 2024. /CFP)