(BIVN) – Severe winter weather conditions are expected or occurring on Mauna Kea or Mauna Loa today, as “falling and blowing snow with strong winds and poor visibilities are likely,” the National Weather Service in Honolulu says.

“This will lead to whiteout conditions, making travel extremely dangerous. Do not travel to the summits,” the forecasters caution.

A rare Blizzard Warning is in effect for the summits, as well as a High Wind Warning.

“Sustained winds up to 80 mph with gusts up to 100 mph will cause whiteout conditions with zero visibilities in snow, blowing snow and dense fog,” the National Weather Service said this morning. “Total snow accumulations 2 to 6 inches are expected.”

The Mauna Kea Access Road is currently closed.

The rest of Hawaiʻi Island is under a Flash Flood Watch. “A developing area of low pressure south of the state will spread deep moisture and unstable conditions across the Big Island,” weather forecasters say. “Periods of heavy rainfall and thunderstorms may result in flash flooding.”

The County of Hawai‘i took the unusual precaution of closing all county parks on Saturday, and telling residents they should “consider canceling or postponing outdoor activities” due to the expected storm.