Update:  29 Jul - Sun - 10:00 pm

YellowstoneNational   Park officials report that the Arthur Fire that closed the park's East Entrance Road to all inbound and outbound traffic earlier today is now estimated at around 800 acres. The entrance was closed at approximately 2:00 p.m. on Sunday, July 29, because of heavy smoke and the potential for fire reaching the roadway from the Arthur Fire. The Arthur Fire was reported between 1-1:30 p.m. on Sunday when heavy smoke was observed south of the East Entrance Road (in the SylvanPass area) near TopNotchPeak. This fire was most likely started by lightning on July 28. The fire is burning very actively in heavy fuels and is currently located approximately 3 miles from the East Entrance of the park. The fire is located on the south side of the East Entrance Road. This fire is being managed under the Unified Command system with the ShoshoneNational   Forest.

Park staff have been in full suppression mode since the fire was first reported. Air tankers were able to do two fire retardant drops, but winds prevented further drops. An incident management team should be in place within the next couple of days, along with additional related fire resources. A number of resources are being utilized on the fire, including fire engines from Park County, Wyoming, and the park and irrigation systems to protect structures. Park staff and their families at the East Entrance have begun evacuation procedures.

Park officials remind visitors that all entrances, except for the East Entrance, remain open, as well as all visitor and park facilities, including all lodging, food services, general stores, gift shops, and campgrounds. The nighttime closure (9 p.m. to 9 a.m.) between Madison and Norris for road construction remains in place.

Current temperatures have been in the 80s, with relative humidity around 12 percent. Winds have been at 20 mph, with gusts up to 40 mph. The forecast for tomorrow is calling for cooler temperatures in the 60s and 70s, with decreasing winds and higher humidity.

Update:  29 Jul - Sun - 5:26 pm 

Yellowstone National Park officials report that the park's East Entrance Road was closed at approximately 2:00 p.m. on Sunday, July 29, to both inbound and outbound traffic because of heavy smoke and the potential for fire reaching the roadway from the Arthur Fire. The Arthur Fire was reported between 1-1:30 p.m. on Sunday when heavy smoke was observed south of the East Entrance Road (in the Sylvan Pass area) near Top Notch Peak. This fire was probably started by lightning and is burning very actively in heavy fuels approximately 11-12 miles from the East Entrance of the park. Park staff have responded to the fire to begin suppression efforts. Additional resources have been requested to assist with full suppression efforts. 

Fire activity during the early portion of the season has been minimal. However, with recent lightning strikes occurring in and around the park and continuing warm weather and high winds, fire activity has increased. So far this season, Yellowstone has had 14 fires - three were human-caused and two were caused by downed powerlines. The remainder were natural (lightning). 

Yellowstone Fire Management policy requires that all human-caused fires be suppressed but that natural fires be allowed to burn as long as they do not threaten people, property or resource values. Before any wildland fire is allowed to burn, however, it must be carefully evaluated and meet an inventory of pre-established criteria (including current and forecasted weather and wind conditions, fuel moisture levels, site location data, and sufficient resources). If all criteria are not met on a daily basis, the fire must be reassessed to determine whether it will still be allowed to burn or if it must be immediately suppressed. When the earlier wildland fires were ignited by lightning, it was determined that they would not likely spread and could be managed as wildland fires to benefit the natural resource. The Ash, Cascade and Douglas Fires will continue to be monitored daily to assure they continue to meet and remain within the established criteria. The Inkspot Fire and the Arthur Fire will be suppressed.