Valentine’s Day left the Washington region under an icy spell, knocking out power for more than 100,000 customers, shutting schools and delaying the work of the federal government.

And the situation could get worse. The wintry weather system that created havoc over the metropolitan region Wednesday was expected to pull in high winds and colder air from Canada and the Great Lakes, according to the National Weather Service. Temperatures could sink to 15 degrees with a wind-chill factor of zero early Thursday. Wind gusts were expected to reach 35 mph, with sustained winds of between 15 and 20 mph.