MIDLAND, Texas (NewsNation Now) — Snow blanketed parts of southwestern Texas on Thursday, where forecasters say up to 18 inches could accumulate in higher elevations of the region and a wintry mix of sleet and freezing rain is expected to make travel difficult to impossible.

Oklahoma Gov. Kevin Stitt issued and emergency declarations for much of the state, and a winter storm warning was in effect in the region until Friday, extending as far north as northwestern Oklahoma, where up to 6 inches of snow is forecast.

Nearly 20,000 Oklahoma homes and businesses were without power early Friday after a winter storm dumped snow and ice across a large swath of the state.

The website PowerOutage.US reported 19,238 outages in the state, mostly in Cleveland and Oklahoma counties in central Oklahoma.

The National Weather Service in Norman said the heaviest accumulations of snow appeared to be on the western side of the Oklahoma City metro area, with 3 to 6 inches reported.

Sleet and freezing rain were falling in San Angelo, Texas, according to National Weather Service forecaster Kelli Barendse, who said the total amount of snowfall will be affected by when the precipitation becomes snow.

“It really depends on when the wintry mix transitions over to snow, we’re anticipating late this morning or early this afternoon,” Barendse said.

No damage was immediately reported.

In Odessa, Texas, in the Permian Basin oil patch, a winter weather shelter was opened that would be available through Friday. Federal guidelines for social distancing to stop the spread of COVID-19 will be enforced at the shelter, the city said.