Just over a week after Hurricane Lala brought destructive flooding to Hawaii, the Big Island is facing another round of tropical downpours as Tropical Depression Moke passes several hundred miles south of the state.
Moke weakened from a tropical storm into a depression on Sunday, August 23, but the loss of wind strength has not removed its main threat. Deep tropical moisture circulating around the system continues to spread across the Hawaiian Islands, with the Big Island bearing the greatest risk of additional heavy rainfall and flash flooding.
Tropical Storm Moke passes to the south of Hawai'i as it weakens into a tropical depression, bringing heavy rain to the Big Island. pic.twitter.com/Xq62ovuPbe
— CIRA (@CIRA_CSU) August 24, 2026
A Flood Watch remained in effect for Hawaiʻi Island on Monday, August 24, as forecasters warned that already saturated ground could allow new downpours to generate rapid runoff, localized flooding and landslides.
Moke weakens, but its moisture remains
Late Sunday, Moke had maximum sustained winds near 35 mph (55 km/h) while moving west at around 13 mph (21 km/h). Its center was tracking well south of the main Hawaiian Islands, meaning a direct strike from the cyclone’s core was not expected.
Outer bands of Tropical Storm Moke have begun in Hilo, Hawaii. 8:15 am local time. pic.twitter.com/goFha7XL79
— Robert Ray (@RobertRayWx) August 23, 2026
The storm’s northern flank, however, contains a substantial plume of tropical moisture.
As this moisture reaches the Big Island, easterly and trade-wind flow pushes the humid air against the island’s steep volcanic terrain. The air is forced upward, where it cools and condenses, enhancing rainfall along windward and elevated areas.
This process, known as orographic lift, means significant rainfall can occur even hundreds of miles from the center of a tropical cyclone.
Earlier forecasts indicated widespread totals of 5 to 10 inches (125 to 250 mm) across parts of the Big Island, with isolated accumulations approaching 15 inches (380 mm). Maui could also experience periods of heavy rain as Moke continues westward.
Saturated ground raised the stakes even higher
Moke’s timing is particularly concerning because Hawaii has had little time to recover from Hurricane Lala.
Lala brought extreme rainfall, damaging winds, flooding and widespread power outages to the islands just over a week earlier. Some locations received more than 3 feet (900 mm) of rain, leaving soils saturated and parts of the road and drainage network damaged.
Thousands of residents were still dealing with power and infrastructure problems as Moke approached.
Even rainfall considerably less extreme than Lala’s could therefore cause problems. Saturated soil absorbs water less efficiently, allowing more rainfall to become surface runoff and increasing the potential for streams to rise quickly.
Steep terrain also makes parts of the Big Island vulnerable to mudslides and debris flows during intense tropical rainfall.
Flooding still remains the main danger
Moke is expected to continue weakening as it moves farther west, potentially degenerating into a remnant low. That weakening trend should gradually reduce its wind threat.
For Hawaii, however, the cyclone’s classification is less important than the moisture it leaves behind.
Humid tropical air combined with persistent trade winds and the Big Island’s mountainous terrain could keep showers locally intense even as Moke’s circulation becomes increasingly disorganized.
The National Weather Service expects breezy trade winds to continue through the first half of the week. With the ground still carrying the scars and water load from Lala, additional downpours could quickly renew flooding in the hardest-hit communities.
