Minute by minute: how Mill Valley stopped Monday's Hillside Avenue fire

A vegetation fire broke out on the ridge above Hillside Avenue Monday afternoon, drawing a fast, multi-agency response that included two aircraft flown in from Santa Rosa and a helicopter PG&E keeps stationed in Novato for exactly this kind of emergency. Firefighters stopped its forward progress in under 90 minutes. No evacuations were ordered. No structures were damaged.

Here is how the afternoon unfolded, pieced together from Southern Marin Fire's own updates, Mill Valley Police advisories, Watch Duty's incident log, Flightradar24 flight-tracking data and on-scene reporting by the Briefing.

What's happening: Southern Marin Fire, Mill Valley Police and mutual aid crews responded to a reported vegetation fire between Hillside Avenue and Blithedale Ridge at 4:42pm Monday. By 6:10pm, firefighters had stopped its advance and contained it at approximately 1.5 acres, with a hose line established around the perimeter. Crews remained on scene overnight and the next day patrolling hot spots. The cause remains under investigation.

The background: The fire moved through vegetation that had previously been treated, at a slow rate of spread. Southern Marin Fire says that treatment work made a real difference. The district believes fuel break work and other preventative measures carried out in the area over the past several years helped limit how far the fire could spread, according to Kim Huff.

The scale of Monday's air response was also unusual for this area. Above Hillside Avenue near Mayor's Lookout, the Briefing found three firefighters stationed for the day to watch for any re-ignition. One said he couldn't remember a plane making a drop near the city of Mill Valley in the last 30 years, a personal recollection rather than a documented figure, but a sense of just how rare Monday's response was for people who do this for a living.

Two of the three aircraft that responded have their own institutional history. Cal Fire has used the OV-10A Bronco as its primary command and control aircraft on wildland incidents since acquiring the fleet from military surplus in 1993, according to the agency's own aircraft specifications. The Black Hawk helicopter is part of a newer program: PG&E has stationed dedicated firefighting helicopters in Marin County since 2023, one of three counties in a program that has logged more than 2,600 water drops since it began, according to a July 2 PG&E news release. Local fire agencies direct the aircraft during an actual incident, not PG&E itself.

The timeline: Aircraft movements below are drawn from Flightradar24 flight-tracking data reviewed by the Briefing. Fire status updates are drawn from Watch Duty's incident log, which attributes them to Incident Command and Air Attack, as well as a Briefing review of agency broadcast channels.

4:41 to 4:42pm Dispatch is received. Southern Marin Fire, Mill Valley Police and mutual aid respond to a reported vegetation fire between Hillside Avenue and Blithedale Ridge.

4:49pm Watch Duty opens the incident. Smoke is visible on a camera at Wolfback Ridge.

4:56pm A Sikorsky UH-60A Black Hawk, one of the helicopters PG&E places in Marin County each wildfire season, departs Gnoss Field in Novato and arrives over the fire at 5:03pm, seven minutes later.

5:04pm A Cal Fire OV-10A Bronco departs Santa Rosa's Sonoma Air Attack Base.

5:05pm A Cal Fire S2T air tanker departs the same base.

5:07pm The Black Hawk helicopter makes its first water drop, four minutes after arriving on scene, drawing from a pond near the Bay Club in Corte Madera. It makes three drops from that source, then switches to Phoenix Lake for four more.

5:16pm The tanker and the OV-10A arrive over the fire. The tanker begins circling at roughly 1,800 feet. The OV-10A holds higher, at roughly 3,000 feet, the role Cal Fire calls its primary command and control platform on wildland incidents.

5:17 to 5:33pm Air Attack's estimate of the fire grows from about 1 acre to about 1.5 acres in timber and brush, per Watch Duty.

5:22pm The tanker makes its first and only drop, descending to about 600 feet for the run, then leaves the area.

5:35pm Incident Command reports resources making good progress, per Watch Duty.

5:37pm Mill Valley Police issue a public advisory urging residents to avoid the area, per a Nixle alert.

5:41 to 5:48pm The OV-10A leaves the area, after circling the fire sixteen times to direct the tanker and helicopter from above. Seven minutes later, the Black Hawk has made the last of its seven water drops and leaves the area as well.

6:10pm Southern Marin Fire reports forward progress stopped, the fire contained at about 1.5 acres.

6:24pm Mill Valley Police confirm no evacuations were necessary and no shelter in place was needed at any point, per a Nixle alert.

Overnight Crews remain on scene, patrolling hot spots and strengthening containment lines, per Southern Marin Fire.

The air response: Three aircraft worked the fire in the space of about 45 minutes, each with a distinct job. The OV-10A flew highest and stayed longest, orbiting at 3,000 feet to coordinate the other two from above. The tanker worked briefly and precisely: three passes at altitude to assess the terrain before a single low run to deliver its retardant. The helicopter did the sustained work, seven total drops from two different water sources over most of an hour.

Huff said air resources on a fire like this get dispatched one of two ways: automatically, under a predetermined response for vegetation fires, or requested directly by the incident commander once crews assess conditions on the ground. Locally, those requests run through the Marin County Fire Emergency Command Center and Cal Fire, which assigns available aircraft based on fire behavior, weather, terrain, access, proximity to structures and competing incidents elsewhere in the state.

The process stays fluid throughout an incident, with the incident commander adding or releasing resources as conditions change, which matches what the flight-tracking data showed Monday: aircraft arriving in a tight window, working briefly, and being released as containment held.

What's at stake: For families closest to the fire, Monday forced a harder decision than most residents faced. Candace was on her deck with her two young sons, ages 3½ and 16 months, when the sirens started.

"As a parent, it didn't feel wise to stay home while helicopters were dropping water so close to us," she told the Briefing. "We quickly packed a few essentials, loaded the kids into the car, and left for a while. Several of our neighbors with young children made the same decision as we all waited for clearer information."

She and her family returned once the fire's advance had been stopped, grateful for how quickly crews responded and relieved it hadn't been a windier day.

Why it matters: Southern Marin Fire's assessment that prior fuel break work slowed Monday's fire is a direct, on-record answer to a question that follows every brush fire near homes: does vegetation management actually work? According to Kim Huff, the district believes it did here. We reported on the fuel brake project here.

The response also doubled as a live test of regional coordination, drawing mutual aid from Central Marin, Tiburon, Marin County Fire and the Tamalpais Crew alongside Southern Marin Fire itself, according to Kim Huff, plus Cal Fire aircraft from Santa Rosa and a PG&E-funded helicopter based in Novato.

For residents, the fire was also a reminder of how they found out in the first place. In a Nextdoor thread, residents credited two apps, Watch Duty and PulsePoint, as the first, and sometimes only way they learned a fire was burning nearby.

The investigation: The cause remains under investigation. The Briefing found Deputy Fire Marshal Marshall Nau on the hillside above Hillside Avenue Tuesday afternoon, walking the area with fire inspectors. He said the investigation was ongoing and inspectors couldn't yet discuss specifics. He did point to one hazard investigators are weighing in this kind of terrain generally: burning pine cones that can roll downhill, a real risk given the fire's position just above the base of what he described as a narrow, canyon-like drainage.

What's next: Southern Marin Fire is planning a community event in response to the fire, expected within the next couple of weeks, according to Kim Huff. Details weren't available at publication time.

What to do to stay prepared

Mill Valley's 12U All-Stars, the last Mill Valley Little League team still playing this summer, saw their season end Tuesday with a 9-4 loss to Chico Eastside in the Northern California state tournament, two days after keeping their run alive with an 8-6 win over Los Gatos.

Monday: Mill Valley 8, Los Gatos 6 - Facing elimination, Mill Valley answered. They jumped ahead 5-0 in the first inning, but Los Gatos answered with three runs in the bottom of the first and three more in the second to take a 6-5 lead. Tate Shackleton came on and settled things down, earning the win with five strikeouts over 2.2 innings, and Tyler Feduska closed it out with two scoreless innings.

Laszlo Winn went 2-for-4 with two runs scored, and Cooper Maddex added three hits. Paxton King and Calvin Boehle each drove in two runs.

Tuesday: Chico Eastside 9, Mill Valley 4 - Mill Valley led 3-0 through three innings. Laszlo Winn doubled and scored in the first on a Paxton King single, then reached again in the third and scored on a two-run home run from Cooper Maddex. But Chico Eastside answered with five runs in the fourth to take a 5-3 lead, and Mill Valley could not catch back up. Wyatt Droege doubled and scored on a Calvin Boehle single in the fourth to cut the deficit to 5-4, but Chico Eastside added a run in the fifth and three more in the sixth to close out the win.

By the numbers: Mill Valley finished tournament play 12-4, having won District 3 and Section 1 before reaching the state tournament. Mill Valley was one of four teams still alive in Chico at the time of Tuesday's loss, out of a field that started with roughly 290 teams at the district level in Northern California.

Looking back: The season marks the deepest state tournament run for a Mill Valley 12U team since 2014, and caps a summer that saw two Mill Valley teams, the 12U and 14U All-Stars, both reach the state tournament for the first time in league history.

🪄 Wednesday on Stage: Magician Perry Yan, Mill Valley Public Library Outdoor Amphitheater, 3:30-4:30pm. Bring the kids to 375 Throckmorton Ave for a high-energy, interactive magic show packed with astonishing illusions, comedy, sleight-of-hand tricks, and engaging storytelling that gets the audience in on the act. Free entry; designed for families and children of all ages.

🏛️ Special Mill Valley City Council Meeting, Council Chambers at City Hall, 5:30pm. The Council meets at 26 Corte Madera Ave for a major agenda including public hearings on proposed sewer fees for FY 2026-27 and forming Community Facilities District No. 2026-1 for municipal services, plus a pilot safety program for Miller Avenue at Montford and La Goma, before entering closed session on pending Hauke Park lawsuits. Public comment available in person or via eComment.