BELLEVUE, Wash. -- Even through the viewfinder of his video camera -- Ray Oen could hardly believe the mud cascading -- and the rocks crashing down his street.

"The whole street was a river of mud and rocks," said Oen.

VIDEO: Eyewitness: Mudslide 'Like A River Coming Down'
SLIDESHOW: Mud Covers Bellevue Neighborhood

A strong thunderstorm, lasting 45 minutes, brought a foot of mud and rocks from the top of Cougar Mountain to the 7000 block of 169 Avenue Southeast in south Bellevue.

“I told my wife to get the video camera just to record this, because it's something we probably won't see here again. Hopefully won't see here again," said Oen.

Construction workers who saw the mudslide where it started said it was knee-deep and moving fast.

“It was amazing. I've never seen anything like it, except for on the news before," construction worker Naomi Neher said.

Those contractors stopped building homes, and started a massive muddy cleanup.

“The whole hillside just looked like a river coming down, a muddy gushing river," said Neher.

The engineer who designed the storm drainage system for this neighborhood, Ed Mecum, said the rocks, some the size of softballs and basketballs, were put at the top of the hill to keep a mudslide from happening. He said the rain came so fast that the rocks were ripped out.

“The storm event that came through here was so massive and so intense at one time, that there was no way for the erosion control system and even the permanent storm system to keep up with it," said Mecum.

Crews continue to cleanup the neighborhood Thursday night. No structural damage and no injuries have been reported.