GORHAM, N.H. — The moment you step out into the frozen air on the way up Mount Washington — one of the most frigid spots in the lower 48 — the icy wind steals your breath and freezes your eyelashes. You can’t blink. The cold stabs your face and numbs your earlobes to rubber.

“It’s an icy hell,” said Amy Loughlin, 50, who was visiting from Austin, Tex., and scaling the mountain, the highest in the Northeast, in the back of a SnowCoach — a van retrofitted with tanklike treads to handle the blowing snow and treacherous roads.

With much of the Northeast and Midwest feeling like a block of ice, the temperature here in the high peaks of New Hampshire’s White Mountains was forecast to drop to 40 degrees below zero overnight Friday. The wind chill could make the air feel as cold as 100 below zero. That is not a typo. Negative. 100.

“We should end up being the coldest location tonight in the lower 48,” said Mike Carmon, senior meteorologist at the Mount Washington Observatory, who was one of a handful of scientists and others huddled at the top of one of the most dangerous and forbidding places in the country. “We basically just start saying it’s stupid cold outside.”