TOULE, Wash. -- The Johnston Ridge Observatory reopened for the season Friday and admission will be free on Sunday, the 28th anniversary of the Mt. Saint Helens eruption.

However, warm temperatures expected this weekend have transportation experts monitoring Washington's mountain pass highways for avalanche control work. The Northwest Avalanche Center has also issued warnings for back country areas.

The reopening of State Route 504 and Johnston Ridge restored access to a monument that has been largely inaccessible due to roads blocked by record snowfall, officials said.

Check road conditions

Visitors can gaze into the crater at the steaming lava dome, view North America’s youngest glacier and learn how the landscape was reshaped by the 1980 eruption. The visitor center offers live seismographs, geologic exhibits, 16-minute eruption movie, ranger-talks and a bookstore.

Admission on the 28th anniversary of the 1980 eruption is free.

USGS Geologist Joe Walder will speak about the recent eruption and the amazing changes in the Crater Glacier at 11 a.m. and 2 p.m. in the auditorium at Johnston Ridge.

“It’s great to regain access to Johnston Ridge and reopen in time for the 28th anniversary,” said Tom Mulder, Monument Manager.

“Our May 16th reopening is the result of long hours of hard work by crews from the Washington State Department of Transportation who cleared record snow from the highway. Our staff has also been working hard to dig out the building from 25 foot snow drifts and prepare the visitor center for Friday’s reopening. It has truly been a collaborative effort by a dedicated group of people.”

The visitor center will be open daily from 10 a.m. to 6 p.m. through October. Admission to Johnston Ridge and Coldwater Lake is $8 per person. Kids 15 and under get in free.