Hawaii Braces for Landslides and Washouts From Olana’s Heavy Rain

Tropical Rainstorm Olana is dousing Hawaii with repeated rounds of heavy rain, raising the threat of flash flooding and road washouts in areas that are typically immune to tropical weather impacts. Here is the latest on the beating that Hawaii is taking at the hands of Olana.

What is Left of Olana Targets Hawaii

While the former Tropical Storm Olana is beginning to dissipate, it is still packing a punch as it skirts by the Hawaiian Islands. What is most notable about this feature is that it is impacting areas that are usually protected by the trade winds.

Forecasters put Hawaii on alert last week as Olana began to show signs of organization in the Central Pacific. The disturbance intensified and reached the status of a tropical storm at its peak. While Olana has weakened slightly, it is still capable of dumping life-threatening rainfall across Hawaii.

Although Olana ignited well west of Hawaii, the upper-level atmospheric winds directed the moisture to the east across the islands. This island chain is not accustomed to seeing storms arrive from the west.  The rain coming from this part of the Pacific will translate to the greatest threats across the south- and west-facing shores of the islands. The mountain slopes in this region will also be under the gun for the torrential rain. This impact zone includes communities that are generally drier due to the northeasterly trade winds.

The steady stream of moisture is forecast to persist through Thursday night. Widespread rainfall totals of 1 to 2 inches are predicted across much of the islands. The central islands of Maui and Oahu will pick up the greatest amount of rain, with 4 to 8 inches likely by the time that Olana wraps up.

The highest elevations of Maui are bracing for 8 to 12 inches of rain. The most potent bands of rain could trigger rainfall rates of 1 to 3 inches per hour. Rain coming down this furiously will naturally increase the risk of flash flooding, debris flows, and mudslides.

Local officials are also warning residents that road and bridge washouts are a possibility. Never attempt to drive across a flooded roadway, as you can often not tell how deep it is with the naked eye. In addition, the water may be obstructing pavement that has washed away.