>> you need to evacuate to an area safe. >> reporter: the governor declaring a state of emergency, evacuating more than 1,000 residents. at least four killed in the west, including the driver of this taxi after his vehicle plunged into the water. our rob marciano is in napa county. >> reporter: the rain stopped here about 12 hours ago, but the water is pouring over the top of this dam. it's normally dry, but today, flowing at 1,000 cubic feet per second. that dam is 70 years old holding about 40 million gallons of reservoir water. >> reporter: in the sierra nevada, this is all that's left of the "pioneer cabin" tree, the famous giant sequoia hollowed out in the 1880s. meanwhile, much of the rest of the country, still freezing after ice storms killed at least four in the south, and brought snow and accidents all the way to the northeast. here in reno, the truckee river runs right through downtown, and bridges were threatened as the waters rose several feet above flood levels. officials hoping it drops tonight because they have more