Mauna Kea, Hawaii — What is happening: The high summits of Mauna Kea and Mauna Loa are under a Tropical Storm Warning through Saturday morning, with some of the island's strongest winds expected: 45 to 55 mph sustained, gusting to 65 mph. A Flood Watch also covers the summits, with another 4 to 8 inches of rain on the way. Local impacts: Wind at altitude can be fierce — gusts strong enough to damage structures, topple equipment, and make exposed roads dangerous. Heavy rain adds flash-flood risk to low crossings below. Scattered outages of power and communications are possible. What to do: Avoid the summits and other exposed high ground until the warning passes. Watch for flash flooding on roads below the summits. Heed any flood watches and warnings — conditions can turn deadly fast. Source: National Weather Service Honolulu. Tropical Storm Warning issued September 25 at 4:59 AM HST.