Flash Flood Watch, High Surf Warning in Effect for Big Island

Wednesday, Aug 22, 2018, 5:11 AM

A Flash Flood Watch and High Surf Advisory and Warning are in effect for portions of the Big Island.

FLASH FLOOD WATCH IN EFFECT THROUGH FRIDAY NIGHT

As Hurricane Lane approaches the islands from the south, deep tropical moisture associated with Lane will spread across the island chain from the southeast, with increased potential for heavy rainfall and flooding.

Abundant moisture from Hurricane Lane is expected to move over the Big Island this afternoon and spread northward to the rest of the islands through Friday. Heavy rainfall is expected, especially along southeast and east facing slopes. Storm total rainfall amounts greater than 20 inches are possible. The flooding threat will increase as Hurricane Lane approaches.

In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage.

PRECAUTIONARY/PREPAREDNESS ACTIONS

A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION.

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Coastal Hazard Message
National Weather Service Honolulu HI
521 AM HST Wed Aug 22 2018

HIGH SURF WARNING FOR SOUTH-FACING SHORES THROUGH END OF WEEK

Life-threatening surf is expected along exposed south facing shores of all Hawaiian Islands through the second half of the week as Hurricane Lane approaches and moves through the area. In addition to the surf, rising water levels due to storm surge will be possible, especially as Lane nears the smaller islands Thursday through Friday. Inundation over vulnerable low-lying coastal areas due to a combination of surge and surf will be possible, especially around the normal high tide cycles.

Surf may rise to 8 to 12 feet along south-facing shores this afternoon, then to 15 to 20 feet Thursday through Friday.

Expect ocean water surging and sweeping over beaches, coastal benches, lava flows, and roadways, creating the potential for significant damage to coastal properties and infrastructure, including roadways. Coastal evacuations and road closures are possible. Large breaking waves may affect harbor entrances and channels with significant damage possible to docks, piers, ramps, and boats.

PRECAUTIONARY/PREPAREDNESS ACTIONS

Due to potential hazards and emergency vehicle operations, travel in coastal areas and ocean recreation should be avoided. Large, breaking surf, significant shorebreak, and dangerous currents make entering the water extremely hazardous. Anyone entering the water could face significant injury or death.

HIGH SURF WARNING REMAINS IN EFFECT UNTIL 6 AM FRIDAY for KONA & SOUTH BIG ISLAND

Expect surf 15 to 25 feet along the Ka‘ū and Puna coast. Surf along the Kona coast will quickly rise to 8 to 12 feet with locally higher waves possible through the day Thursday.

Expect ocean water surging and sweeping over beaches, coastal benches, lava flows, and roadways, creating the potential for significant damage to coastal properties and infrastructure, including roadways. Coastal evacuations and road closures are possible. Large breaking waves may affect harbor entrances and channels with significant damage possible to docks, piers, ramps, and boats.

PRECAUTIONARY/PREPAREDNESS ACTIONS

Due to potential hazards and emergency vehicle operations, travel in coastal areas and ocean recreation should be avoided. Large breaking surf, significant shorebreak, and dangerous currents make entering the water extremely hazardous. Anyone entering the water could face significant injury or death.