A small sinkhole formed in Dimond Park near Thunder Mountain High School Thursday afternoon.

George Schaaf, parks and landscape superintendent, said a sinkhole about a foot wide at its mouth and five feet deep opened up on land maintained by Parks and Recreation near the athletic fields by the high school.

“It was in the grassy area between the new bike path and the curb that runs around the perimeter of the ball field,” said Schaaf.

The sinkhole was reported to Parks and Recreation by the Public Works Department’s Streets Division and the Juneau School District, according to Schaaf and JSD chief of staff Kristin Bartlett.

“It’s not actually on the school grounds, so the custodial department over at Thunder Mountain went and checked it out,” Bartlett said. “They put some cones around it so it was obvious that it was a dangerous area there.”

“We’ve got it barricaded off,” Schaaf confirmed. He said the sinkhole did not impede traffic, and no injuries were reported.

Sinkholes form when the rock, clay or soil beneath the ground’s surface is dissolved or washed away and the surface collapses.

“It does happen from time to time,” Schaaf remarked.

Schaaf said he is not an expert on how the sinkholes form or what causes them, but he added, “I wouldn’t be surprised if the amount of rain we’ve had recently had something to do with it.”

According to the Juneau Forecast Office, 5.71 inches of rain have fallen this month at Juneau International Airport, as of 3 p.m. Thursday.

A contractor worked to fill in the sinkhole as Schaaf spoke Thursday afternoon.

At this time, Parks and Recreation is not concerned about any other sinkhole formation activity in the area, according to Schaaf.

“It looks like it didn’t extend beyond the area that they opened up, so we don’t really expect it to … continue expanding,” Schaaf said.

• Contact reporter Mark D. Miller at 523-2279 or at mark.d.miller@juneauempire.com.