States in the US Pacific Northwest are bracing for one of the worst snowstorms the region has seen in a generation.
A westerly storm is expected to engulf the state of Washington, bringing up to 2ft (61cm) of snow, the National Weather Service (NWS) says.
Mountainous areas already hit by a weekend storm will be hardest hit, with areas of Oregon also seeing deep snow.
Seattle officials fear the storm could bring the heaviest snow at the city's airport since 1985.
Travel could become dangerous or impossible in the region, weather forecasters said.
The NWS described the upcoming snow storm as a "classic overrunning scenario" seeing an approaching warm front drawing cool air down from British Columbia, across the border in Canada.
Most of the Washington lowlands will receive 5-10in (13-25cm) of snow overnight on Tuesday and into Wednesday, the NWS said - equivalent to the city's annual snowfall in one day.
Other forecasters suggested the snow levels could be even higher.
Weather officials in Canada were keeping their eye on the storm front. Vancouver has already seen snow and ice, with concerns that Wednesday's heavy snow could head over the border and into British Columbia.
"That front will flirt with the border area," David Jones of Environment Canada told the Vancouver Sun.
"Does it pull to the north and hammer us, or does it remain to the south? Right now it's not clear."