EAST PALESTINE, Ohio (WJW) — The scheduled release of toxic chemicals from several derailed train cars created a thick, black plume that could be seen from weather radar.

Governors in Ohio and Pennsylvania on Monday ordered everyone living in a 1-mile by 2-mile area around the site to evacuate ahead of the release, intended to relieve building pressure inside the derailed cars and avoid a potentially “catastrophic” explosion.

The plume was visible Monday from Pittsburgh weather radar, reported FOX 8 meteorologist Mackenzie Bart.

The region’s low wind speeds on Monday evening of at most 5 mph, meant the plume remained somewhat stationary, said Bart. Winds are expected to shift in from the north and begin pulling that smoke farther south by about midnight, she said.

Those living south of the site may notice lingering clouds but they could be cleared by the coming rain.