A huge landslide on Whidbey Island in western Washington knocked one home off its foundation and caused the evacuation of more than 30 others after a stretch of land the length of five football fields fell from the island ridge.

No one was reported injured in the landslide, though at least five homes are said to be in immediate danger as the ongoing landslide levels out.

The slide occurred early Wednesday morning on the island community of Ledgewood, about 50 miles north of Seattle, startling residents with what some said sounded like a sonic boom.

"The ground shook. It was like an earthquake," said Bret Holmes, who was staying in a home in the neighborhood when the landslide occurred, according to Seattle news station King 5.

The hillside home where he was staying is in danger because of the landslide.

"It makes me want to throw up," he said. "We lost half of the back yard all at once. Fifteen trees. And we've lost another 25 feet since then. I'm just worried none of it will be here when I get back."

Microsoft CEO Steve Ballmer reportedly has a home on the island, but it was not threatened by the landslide.

Many of the threatened homes are summer cabins and weekend getaways and were not occupied.

Whidbey Island's west side is prone to prone to landslides because of soil conditions and water movement in the ground, the Associated Press reported, citing Central Whidbey Fire and Rescue Chief Ed Hartin.

However, no significant rain has fell on the island in recent days.

We have no specific cause as to 'why here, why now, why this big," said Hartin.

As the ground as not stablized, state geologists say it will be a couple of days before they can determine when it is safe for homeowners to return.