SAN FRANCISCO (AP) — Northern California and southern Oregon residents are bracing for a “bomb cyclone” weather phenomenon that’s expected at one of the busiest travel times of the year.

The National Weather Service says the storm expected Tuesday into Wednesday could be like nothing experienced in the area for 20 years.

Wind gusts of 75 mph are expected in some areas in some areas and waves of 35 feet or more could slam the coast.

Mountain passes in northern California and southern Oregon could get up to two feet of snow.

The center of the low-pressure system is expected to make landfall late Tuesday afternoon between Crescent City, California, and Brookings, Oregon.

A “bomb cyclone” forms when air pressure drops by 24 millibars in a 24-hour period.

Forecasters say this storm’s air pressure has dropped even more quickly than that.

To find out when the rain will hit your area, use KRON4’s Interactive Rain Radar.