Updated 8:29 p.m. PDT Sept. 17, 2022
As expected, when the winds increased Saturday afternoon the activity on the east side of the Mosquito Fire picked up. Wind gusts measured at the Foresthill weather station began exceeding 15 mph at 11 a.m. and peaked at 24 mph at 1:30 p.m. The relative humidity was in the 40s until rising into the 50s at 6 p.m., after which the spread of the fire decreased.
The forecast calls for the RH Saturday night to reach 87 percent while the winds slow to 7 mph out of the south. The winds will increase Sunday out of the south to 15 mph with gusts of 21 to 25 mph. The chance of rain will rise throughout the day Sunday, reaching 66 percent by sunset. Precipitation could continue off and on through Wednesday, possibly exceeding an inch.
The fuels, the vegetation, are extremely dry after years of drought. The rain event will not end the fire season in this part of the state, but assuming the precipitation arrives as expected the spread of the Mosquito Fire should slow to a crawl for several days, at least.
The fire was mapped at 3:58 p.m. Saturday at 73,381 acres.
Firefighters continue to make good progress holding the fire along the Eleven Pines Road and other control lines along the eastern flank. Crews were able to successfully engage in strategic firing operations Saturday to continue building a buffer along these control lines. Saturday night firefighters will patrol, mop up, and secure established control and containment lines in an effort to ensure the fire remains within these existing lines while it is being tested by this wind event.
Placer County is maintaining an evacuation map. Approximately 11,277 people are currently under evacuation orders.
Fire officials said 78 structures have been destroyed. On Saturday there were 3,729 personnel assigned to the fire.
Firefighters are making good progress on the south, west, and north sides of the Mosquito Fire near Foresthill, California.
On the northeast side, the firing operation along Chicken Hawk, Old Foresthill, and Deadwood Roads is complete and is being mopped up. This will reduce the chance of the fire spreading further to the west and northwest.
Below Todd Valley on the west side, another firing operation is tying in that corner of the fire with the Middle Fork American River. Much of the south side from Volcanoville past Quintette is looking fairly secure.
What is left is the east side which this week, pushed by the prevailing winds out of the southwest, has been moving east about a half mile each day. Firefighters are prepping multiple north-south roads out ahead to the east which could serve as indirect firelines when complete.
Two miles east of the fire is the northernmost grove of Giant Sequoias (see map above), trees that can live for 3,000 years during normal climate conditions or if managed and protected appropriately. On Thursday firefighters completed a four-acre burn in this small grove. This was to reduce the fuel so that when the main fire comes through hopefully these huge trees will be protected.
The weather on Friday will be similar to what we have seen for several days, moderate relative humidity and wind. That will change Saturday as a system comes in that starts in the afternoon with strong southwest winds gusting to 23 mph, but the RH will still be moderate, in the upper 30s. These winds could throw out burning embers far ahead of the fire, starting spot fires that could increase the rate of spread significantly. Saturday night the wind will come out of the south at 14 mph and that is when the chances for rain begin. By Sunday morning the chances increase to 50 percent and through Monday will vary, but could be as high as 80 percent. The NWS forecast predicts the amount of precipitation through Tuesday could exceed one inch.