As a winter storm paralyzed the Deep South on Tuesday, a winter weather advisory was in effect on Mauna Kea, where the summit was covered in heavy snow.

Snow on Mauna Kea and rain were expected to continue on Hawaii island through Tuesday night, and a flash flood watch was posted because of the threat of heavy rain and thunderstorms.

To be sure, Hawaii’s winter weather is no comparison to the deep freeze on the mainland, but unstable conditions kept the sun behind clouds for much of the day around the state.

Flooding closed Highway 19 on Hawaii island near Ookala for about three hours until about 3 a.m. The Hawaii island summits and Lanai were also under a wind advisory because of gusts stronger than 50 mph.

High winds on Oahu led to the closure of Foster Botanical Garden on Tuesday afternoon after a large tree was split in half, creating a public hazard. City work crews were called in to take care of a dangling branch, blocking two Ewa-bound lanes of Vineyard Boulevard adjacent to the gardens to remove the branch.

There were no reports of injuries or damage, and city crews planned to return to complete removal of the tree. The park is expected to reopen today.

A leaning pole also led to the closure of two left lanes on Bere­ta­nia Street between Victoria Street and Ward Avenue at about 1:15 p.m. Tuesday, according to Hono­lulu police.

The high-surf advisory for north and west shores of Oahu, Kauai County and Molo­kai and north shores of Maui was extended to 6 a.m. Thursday. Surf on north-facing shores was expected to produce waves at heights of 14 to 18 feet.

Forecasters said beachgoers should expect waves to sweep across beaches. Strong breaking waves and currents can also make swimming dangerous, even deadly for inexperienced swimmers.