2 Fires In Yosemite National Park Forest: Air Quality Is Poor & Multiple Trails Are Closed

Firebrains | FireFire
South Fork Fire, Image: Sierra Fire Watch, Twitter

There are two wildfires burning in the Yosemite National Forest. The South Fork Fire started August 13, 2017 and is 2,407 acres with 7% containment, the Empire started August 1, 2017 by multiple lightening strikes and is currently 1,450 acres.

South Fork and Empire Fire Updates – August 17, 2017

August 17, 2017 Posted by: Yosemite Fire Information

The South Fork Fire experienced minimal growth yesterday as weather conditions and high humidity levels held the fire within the western and southern containment lines. The fire continues to slowly spread to the northeast into the Yosemite Wilderness. The Empire Fire is being managed for both resource and protection objectives. It is approximately 1 mile south of the Bridalveil Creek Campground east of Alder Creek drainage and west of Bridalveil Creek drainage.

  • The Chilnualna Falls trail is closed at the trailhead due to the South Fork Fire, which is currently being suppressed but remains active.
  • The following trails are closed due to the Empire Fire:
    • The trail is closed from near Bridalveil Creek Campground to the junction of the Deer Camp trail.
    • The trail is closed through Westfall Meadows from Glacier Point Road to the Empire Meadows junction.
    • The trail is closed from Bridalveil Creek Campground to the first junction of the trail from the Ostrander Lake trailhead.

Expect smoky conditions in Yosemite

Expect poor air quality and limited visibility due to fires in Yosemite. Avoid strenuous exercise outdoors and remain indoors when possible.

The South Fork Fire grew slightly on Wednesday to 2,407 acres. It is 7 percent contained.,  Image: NATIONAL PARK SERVICE

South Fork Fire In Yosemite National Park, Wawona Community

InciWeb, Incident Report:

Updated: Morning of 8/18/2017

Incident Overview:

8/17 The South Fork Fire experienced minimal growth yesterday as weather conditions and high humidity levels held the fire within the western and southern containment lines. The fire continues to slowly spread to the northeast into the Yosemite Wilderness. Air resources will continue to assist the firefighting effort today as smoke levels allow. Direct line construction was tied into Wawona Dome on the west flank. Burning operations may begin today to allow for the protection of the Wawona community and the Mariposa Sequoia Grove.

Strategic objectives are to hold the western and southern flanks while monitoring the northern and eastern edges. Minimal Impact Suppression Tactics are being used to manage the area of the fire, using natural barriers such as rocks or streams, trails, and other minimal disturbance methods to contain the fire.

Smoke is expected to be heavy in the fire area and adjacent communities and is likely to be very dense in Wawona in the evenings and mornings. Community members who are sensitive to smoke should consult their physician and may want remain indoors or leave the area in periods of heavy smoke. Residents can monitor the air quality links below for current information.

There remains a threat of thunderstorm activity in the fire area today as a weak low pressure system remains over the region.

The South Central Sierra Interagency Incident Management Team (Deron Mills IC) assumed command of the fire at 6:00 AM on August 16th. The SCSIIMT is comprised of employees from state and federal agencies, municipalities, and several local resources to support firefighting personnel in their suppression efforts.

There is a voluntary evacuation in place for the Wawona community.

For additional information:

  • Rapid Notify is a community alert system for rapid event notifications. Register by visiting http://www.rapidnotify.com/customer/Yosemite.html
  • Nixle is a public-safety notification system. Sign up for emergency alerts by texting 95389 to 888-777 or visit their website at www.nixle.com

Basic Information

Current as of 8/18/2017, 7:34:48 AM
Incident Type Wildfire
Cause Unknown
Date of Origin Sunday August 13th, 2017 approx. 02:30 AM
Location 1 mile east of the community of Wawona
Incident Commander Deron Mills
Incident Description Supression

Current Situation

Total Personnel 512
Size 2,407 Acres
Percent of Perimeter Contained 7%
Estimated Containment Date Sunday September 03rd, 2017 approx. 12:00 AM
Fuels Involved Timber (Litter and Understory) Brush (2 feet)
Significant Events Active, running, torching


Planned Actions

As inversions lift, utilize air resources to aid crews in line construction and utilization of natural barriers. Continued need for trail closures as fire continues to actively burn. Construct direct line to tie into existing trail system.

Projected Incident Activity

Voluntary evacuations in Wawona still in place. Fire continues to spread to the northeast. Heavy inversions have grounded aircraft until late afternoon, it is when these inversions lift that most visible fire activity occurs.

24 hours: Continue to aggressively suppress fire spread toward the community of Wawona on the west flank of the fire.

48 hours: Voluntary community evacuations are still in place. Fire continues spread to the northeast.

72 hours: Secure south edge of fire and keep fire contained to south fork of Merced River, secure west flank.


The fire is located in the South Fork drainage of the Merced River, in steep and inaccessible terrain. Crews are hiking in and setting up spike camps in an effort to utilize as much daylight as possible. Pack trains are being considered to support spike crews. The west flank of the fire is approximately 3/4 mile east of the Swinging Bridge in Wawona. The fire continues to pose a threat to Wawona, the Mariposa Grove, US Forest Service lands and a radio and telecommunications site at Wawona point. A combination of air support, direct line construction and use of natural barriers are the current tactics being implemented to meet protection objectives.

Current Weather

A warming and drying trend will be present. Winds aloft will be light and from a generally easterly direction with enough moisture and instability over the Sierra for a threat of showers and thunderstorms each afternoon and evening. Winds will be generally terrain driven, however, any thunderstorm winds will be gusty and erratic in direction. Temperature and humidity trends will show little day to day change.


South Fork Fire, Image: Capture from InciWeb

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