STAR-ADVERTISER FILE Pictured is an overall view of Wahiawa Reservoir from the Kemoo shoreline.

After a torrential downpour on the North Shore on Friday, the Wahiawa Dam is at risk of breaching, the Honolulu Department of Emergency Management said in a news conference. The agency issued a “get ready to go” notice and encouraged those in the area to evacuate “out of an abundance of caution.”

Dr. Randal Collins, director of the agency, said the reservoir’s water level was 83 feet as of 6 p.m. Dam failure occurs at 90 feet, he said.

“There is a risk of dam failure,” Collins said. “A failure could send water downstream fast and lead to catastrophic flooding.”

Collins said those in the area should prepare to evacuate on short notice and those who need extra time should leave immediately.

The Department of Emergency management is monitoring conditions closely and hopes to initiate an evacuation two hours before there is threatening damage to the reservoir or failure of the reservoir, Collins said. A “band of heavy rain,” which could include thunderstorms, could hit the area between 8 p.m. and 10 p.m. He said the agency expects another two to five inches in the area, but thunderstorms can make the rainfall unpredictable.

“That uncertainty is one of the big reason why we are leaning forward on this and taking the caution that we’re taking here.”

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The closest evacuation shelters are at the Wailua Height High and Intermediate School, which is not in the evacuation zone, Kahuku Elementary School and George Fred Wright Wahiawa District Park Collins said. He added that those evacuating should bring sleeping gear, clothes, water, food, medications, important documents, phone chargers and other supplies that can last up to three days if staying at a shelter.

The dam has not shown signs of structural damage, Collins said.