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All you need to know about Hawaii flooding of 2021

Hawaii is supposedly one of the most beautiful islands present on Earth. It is also famous for Pearl Harbor, named so because of the abundance of pearls once upon a time. However, this paradise comes with a lot of challenges. Natural calamities such as floods, storms, tsunamis, lava flows, and earthquakes pose a threat to the islands. Lately, authorities in Hawaii have reported heavy floods and power outages in Honolulu‘s urban areas. Luckily, the state has mainly averted landslides and severe flooding as of Tuesday evening.

Why in news: The president of the US, Joe Biden, paid his homage to the 80th-anniversary celebration Tuesday morning in December 2021 at Pearl Harbor. The rumors of its cancellation were clarified when Navy spokesperson Brenda told this to the Associated Press through an email.

Flash flooding in Hawaiian islands

Let us know a little bit about these dangerous flash floods-Flash floods can occur in specific areas of this big island when it rains heavily. A tiny, peaceful river may be transformed by heavy rain into a cascading flood that sweeps away everything in its path. Every few years, flash floods claim the lives of many and these rains can be difficult to predict and may arrive unexpectedly.

Dangerous Storms Threaten To Bring Catastrophic Flooding To Hawaii

Flash floods are far more prevalent in Hawaii than other natural calamities like tsunamis or storms. Past incidence of catastrophic flooding is here-

In 1992, Hurricane Iniki caused damage to Kauai. Parts of Hawaii’s Kuhio Highway were buried by landslides and water.

A flash flood hit Manoa Valley on Oahu in October 2004, fully flooding the main level of the University of Hawaii at Manoa Hamilton Library. In addition to demolishing portions of the library, the flood destroyed at least 60 dwellings and cost over $1 million in damage.

In March 2006 itself, more than 30 days of severe rain caused massive floods as well as considerable public health hazards. It caused a dam to burst in Kauai, killing seven people. The rain on Oahu caused the sewer system in Waikiki to overflow, resulting in a sewage leak that contaminated areas of the island’s south shore.

In April 2018, on the island chain of Kauai and Oahu, a series of thunderstorms generated record-breaking rainfall. An upper-level low passed across the region, spawning a mesoscale convective storm that traveled through eastern Oahu, dumping 5.55 inches of rain in some areas. Heavy rains resulted in flash flooding and landslides, which flooded roads and carried away numerous abandoned homes. 532 homes were damaged or destroyed as a result of the floods.

March 2021 Hawaii floods

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Image Source: depositphotos
  • Period: March 7 – 15, 2021
  • Location: All of Hawaii
  • Deaths: Unknown, 1 missing

The Hawaii floods of March 2021 were a disastrous sequence of floods that wreaked havoc on the state of Hawaii.

  1. On March 7, 2021( Sunday), massive rains began, flooding the Kaupakalua Dam.
  2. It was claimed that the dam leaked owing to flaws, and it would be decommissioned this summer as a result.
  3. At least a half-dozen homes have been severely damaged or destroyed. The floodwaters also demolished the Peahi Bridge and severely damaged the Kaupakalua Bridge.
  4. On Tuesday morning, more than 1,300 customers in Haiku were without electricity.

Observations of the National Weather Service:

This catastrophic flooding was caused by a seasonal cyclone that dumped heavy rain throughout Hawaii. According to the estimate, some places might have experienced up to 25 inches of rain by Tuesday.

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Photo by Chris Gallagher on Unsplash

On Tuesday, a powerful storm system slammed Hawaii with flash floods and heavy rains for the second day, but the islands were mainly spared landslides and devastating floods.

Honolulu was one of the most flooded locations in the state, with flooding in urban areas caused in part by blocked drains and cars creeping as water gushed out of manhole covers.

The flooded street was “waist-deep” in several parts of the city as predicted by meteorologists of the National Weather Service.

There had not been any news of deaths or injuries, although one woman on Oahu had to be rescued when her home’s wall collapsed.

The Weather Service in Honolulu stated on Tuesday afternoon that parts of Maui were inundated after “a north-to-south-oriented rain band” slammed the island.

There was an alert of a blizzard warning for the state’s highest peak on the big island. Although no residents live at the summit there are telescope observatories and other offices where officials work.

Causes of this flash flooding:

Slow-moving storms fuelled by a powerful low-pressure system fed by plentiful moisture from the tropics poured inches of rain per hour in some regions. The strong winds rushing into the island were a type of Kona low. It is a type of storm in Hawaii that frequently stops, drops enormous amounts of rain in one region, and moves southward, giving moisture to areas that don’t get much rain, according to the Weather Service.

However, given the vastness of the Pacific Ocean, meteorologists say it’s unusual for a Kona low to stall squarely over the Hawaiian islands. The overflowing dam, along with the severe rain, led nearby rivers and streams to overflow, compounding the crisis.

Precautionary measures taken for the Hawaiian islands

The National Weather Service at first canceled the flash flood warning for Oahu, the most populated island, on Tuesday morning. However, it issued flash flood warnings for Niihau and Kauai, Hawaii’s westernmost islands, from Tuesday afternoon until Wednesday morning.

On Monday and Tuesday, Maui County received the state’s highest recorded rainfall of 20 inches, according to the National Weather Service. Over 14 inches of rain fell on sections of Hawaii Island, the state’s largest island, over 12 inches on Oahu, and 4 inches on Kauai during the same period.

As a quick and efficient relief measure, at least four shelters started operating overnight in Oahu.

After-effects of the flooding:

Despite the agency’s warning that many landslides were predicted in regions with steep terrain, no large landslides have occurred yet. However, some roadways here and there were found obstructed by rocks, crashing tree limbs, and downed power lines.

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Photo by Denniz Futalan from Pexels

There was some concern about ground shifting since the rain had begun to sink in for a couple of days, and the people were encouraged to remain off the roadways.

Electric power in downtown Honolulu was not restored until Wednesday morning. Severe flooding damaged homes and washed away several vehicles.

In this state of emergency, the Hawaii gov issued a statement allowing state funds to be used to compensate for losses caused by floods and other cyclone-related damage. Hawaii and Honolulu county mayors have also proclaimed an emergency plan.

The holiday was declared in schools and some offices and only a few people were seen on the roads.

Geographically, being a volcanic area, terrain with steep slopes and people living near them were dealt with utmost care.

Help and assistance

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Photo by RODNAE Productions from Pexels

Following Oahu’s heavy showers and flooding, the Salvation Army organized efficient relief and outreach programs in Haleiwa and Hauula to assist those who were affected. Eligible residents got catastrophe financial help, temporary housing assistance for those who had been displaced by flooding, food, water, and emotional and spiritual support.


When it comes to weather prediction over the Hawaii island chain, it is difficult to establish a direct link between one significant shower and climate change.

However, as the globe heats, intense rainstorms are becoming more common in the United States and other regions of the world. Also, as the world warms, the frequency of these events is certain to rise. The fact that warmer air carries more moisture is one of the most fundamental reasons. So, the local inhabitants are expected to stay aware and take instant precautionary measures to get flood watches.


Last Updated on November 30, 2023 by Namrata123


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