President Donald Trump has approved a major disaster declaration for Hawaiʻi following the destructive Kona low storms last month, Gov. Josh Green announced Wednesday.

The Secretary of Homeland Security told the governor about the decision Wednesday, Green said, describing the initial federal support for response and early recovery efforts as an important first step.

“Being recognized as a major disaster is significant because it opens the door for additional federal resources and establishes a shared responsibility between the state and federal government to support our communities throughout our recovery,” Green said in the release.

The state has estimated $1 billion in damages to public and private infrastructure, schools, roads and homes.

“The recovery from this storm will be long and difficult and will require constant collaboration with the counties and the federal administration — and I am confident that as with other recent disasters, we will benefit from the aloha we share for each other and our collaborative approach with anyone who can offer assistance,” he said.

More: Hawaiʻi Governor Estimates Storm Damage Has Already Hit $1 Billion

The back-to-back Kona low storms last month caused millions of dollars in damage. The University of Hawaiʻi calculated more than 2 trillion gallons of water — enough to fill 3 million Olympic-sized swimming pools — fell in Hawaiʻi during the March storms.

The historic flooding inundated Wahiawā, nearly causing the dam there to fail, threatening several thousand lives and properties. The rural North Shore town on Oʻahu is continuing to clean up the muddy mess, as are other parts of Hawaiʻi, including on Maui and Hawaiʻi island where sinkholes abound and public schools were forced to close due to the damage.

Green made his pitch to the president for a disaster declaration to help the islands last month in a four-page letter. There were concerns that Trump might not approve Hawai‘i’s request, or delay approval, because it’s a Democratic stronghold.