CHEYENNE, Wyo. (AP) — The Wyoming Department of Transportation says it continues work to reopen highways washed out by flooding in Niobrara County.

Flash flooding Thursday destroyed a bridge on U.S. 85 in Lusk and washed out U.S. 18-20 at a culvert in Manville.

WYDOT officials said Monday they're working on a detour that would allow cars and light trucks to bypass the destroyed bridge on U.S. 85. Another option being considered is a temporary modular steel bridge.

Crews are installing a new culvert on the highway through Manville.

U.S. 85 remains closed between Lusk and Wyoming Highway 270 some 30 miles north of town. U.S. 18-20 remains closed between Orin Junction and Manville.