nbc's kirk gregory reports. >> reporter: old man winter is slamming into the pacific northwest.now has been falling steadily in parts of oregon and washington making road conditions hazardous. with the worst expected later today. seattle, more used to rain than snow, is preparing for a major winter wallop. the national weather service has issued a winter storm warning for much of the region, where up to two feet of snow is forecast in the cascade mountains. >> off on 34 and turn around. closed until tomorrow. >> really? >> yeah. >> reporter: interstate 90 was closed tuesday because of avalanche danger. >> the weather does what it wants to do so it's hard to predict. >> reporter: this is the scene about an hour outside of portland. major highways are slick and treacherous as snow plows work to keep up. >> we are expecting more snow so our crews are working 12-hour shifts, 24 hours a day jo around the clock work for a winter storm showing no signs of letting up. kirk gregory, nbc news. >>> elsewhere there was a security scare last night at the white house. the secret service locke