After 10 a.m., warming temperatures escalate the avalanche potential in the pass, said park spokesman Dan Hottle.
To make the pass passage window, those traveling west to the park should depart Cody no later than 8:30 a.m. Heading east, travelers should leave the Fishing Bridge area no later than 9:15 a.m., said the release.
When the pass is closed, the road will be closed between the east gate on the east side and Lake Butte Drive on the west, and signs will be posted, Hottle said.
Limited travel will remain in effect until enough snow has melted in and above Sylvan Pass to remove the avalanche potential there, said the release.
Melting snow also has saturated the ground and washed out about 60 feet of road near Sedge Bay, just west of Lake Butte Drive.
The eastbound portion of the road is unsafe, so only one lane is open. Traffic will be directed by flaggers or automated traffic lights, said the release.
It will take several weeks to make structural repairs to the road, and there will be temporary delays, Hottle said.
“That is where you might encounter a slow-down,” Hottle said.
Still, for the most part, Hottle said, park roads are in good repair.
“We’re trying to keep as much open as we optimally can,” he said.
“Spring has begun arriving in some of the lower elevation areas of the park, such as Mammoth Hot Springs,” said the release. “Other areas remain covered with several feet of snow. Some boardwalks and most park trails may remain impassible for several weeks.”
U.S. 212 from Wyo. 296 (Chief Joseph Scenic Highway) has been open for the last week, so folks can enter the park from the northeast gate by Silver Gate, Mont.
However, U.S. 212 to Red Lodge, Mont., remains closed.
“The north side of the park is pretty open now,” Hottle said.
There is some access to Norris Geyser Basin, he added.
The east gate opened May 6, but closed May 11, due to unstable snow and avalanches.
Since the closure, the howitzer stationed in the pass has fired 18 shots, triggering 13 avalanches, Hottle said.
Travelers are encouraged to check the park’s 24-hour road report hotline at 307-344-2117 for the latest updates, or visit www.nps.gov/yell.