Bighorn Fire, Southern Arizona

Unlike most fires, the lightning started the Bighorn Fire wasn't named by a road, state park, or lightning but named for the bighorn sheep that inhabit the area. The fire, which grew to 119,541 acres and was mainly in the hills above Tucson, some of Tucson's suburbs were forced to evacuate their homes. In the end, no structures were lost.

Conditions weren't far from normal when it came to the first 6 months of the year. We'll look at the weather at Tucson International Airport from January 1 through June 4.

The average temperature was 64.7°, 1.8° above normal. This would be considered normal as anything +-2° from the average would be considered normal. Precipitation was similar as well. Tucson Airport received 2.15" of rain, which is 0.94" below normal. This is a little outside of the normal range which can also be seen in the drought monitor below. As you slide the bar to view the difference in the drought from January 7th to June 9th, the Tucson area did become abnormally dry.

• June 5: Fire Reported
• June 6: 200 acres (Evening Estimate)
• June 7: 1,000 acres (Morning Estimate)
• June 8: 2,300 acres (Morning Estimate)
• June 9: 2,550 acres (Morning Estimate)
• June 10: 3,227 acres (Morning Estimate)
• June 11: 4,769 acres (Morning Estimate)
• June 12: 7,092 acres (Morning Estimate)
• June 13: 10,367 acres (Morning Estimate)
• June 14: 12,345 acres (Morning Estimate)
• June 15: 14,675 acres (Morning Estimate)
• June 16: 15,805 acres (Morning Estimate)
• June 17: 17,492 acres (Morning Estimate)
• June 18: 31,208 acres (Morning Estimate)
• June 25: 81,702 acres (Morning Estimate)
• June 30: 114,991 acres (Morning Estimate)
• July 4: 118,804 acres (Morning Estimate)
• July 23: 119,978 acres (100% Contained)

Fire growth was steady until several elevated and Red Flag days pushed the fire on significant runs highlighted in bold. The fire continued to grow until containment day on July 23rd.

While NWS Tucson office had no Red Flag Warning out the day the fires started (NWS offices in AZ do not issue Red Flag Warnings for dry thunderstorms), the danger of thunderstorms was discussed in the morning Area Forecast Discussion to local fire partners:

Once the fire was ignited, NWS Tucson issued Red Flag Warnings on and off for the duration of the fire as conditions continued to be hot, dry, and breezy to windy. The storms, which ignited the Bighorn Fire were quick moving dry thunderstorms (lightning with little no rain).

The NWS Tucson office began to ramp up messaging 24 hours in advance due to increasing winds and low humidity levels. This included the following.

Early in the morning on June 6th, a lightning strike started a fire in the Catalina Hills and it happened that Shawna Cadwell caught an image of it around 3AM, which can be seen in the tweet below.

NWS offices do their best to find video footage from cameras around the area to share with the public so they can stay informed with the most up to date information.

Briefings continued on the morning of June 8th as the fire continued to grow. The fire was estimated at 2,300 acres and 10% contained. Winds for the upcoming days would be the biggest concern.

NWS Tucson issued a Red Flag Warning for what would become the largest increase in single day acreage during the incident:

The link above highlights the challenging day firefighters had, but ultimately Summerhaven was saved. Pictures below show the massive smoke plume as the fire raged and pushed toward Summerhaven.

Red Flag Warnings were issued for the Catalina Hills as winds continued to increase and the air continued to dry. As of June 28th there was no information on loss of structures.

As the fire continued to grow, it looked as though monsoonal moisture was needed to help gain control of this fire. But then becomes the challenge of the hills that already burned and the potential for flash flooding.

Containment was up to 85% on July 10th as the fire had only grown a little over a thousand acres in 8 days. The heat continued to rage on though, so the battle wasn't over quite yet.

To prepare for the potential of flash flooding, the Tucson Department of Transportation and Mobility issued a graphic on Twitter on areas that could be impacted by flash flooding and runoff from the Bighorn Fire. It's never too early to prepare.

As monsoonal moisture began to move over southwestern US, while it helped firefighters gain control of the fires, flash flooding into Tucson and surrounding areas was a concern. NWS Tucson issued a radar loop on July 16th as scattered thunderstorms moved into the area.

On July 19th, burned debris moved along a channel in Tucson as rain moved over the Bighorn Fire. Remember, while it may not be raining on you, it could be raining upstream so always be aware of your surroundings.

Catalina State Park opened back up in early August and the sight was much different than before.

Despite the charred landscape, locals were eager to get back into the hills.

The post below says it all. While the area may be charred, it will recover.

What comes to mind is this extreme wind event (strongest synoptic wind event so late in June). There was a slopover just above Summerhaven on the NE slope of Mt Lemmon that they were having a hard time with due to all the snags from the Aspen fire. The forecast called for strong winds and in the night-shift briefing I mentioned winds would gust to around 50 mph at the ridge top (just above the slopover).  

As you can see in the attachment, the wind was rather strong on Radio Ridge (peak sustained 49 mph G58 mph!). The next morning in the pre-ops briefing, the night ops Chief Steve Creech confirmed that it was very windy as he was parked on the ridge as a lookout. His comment - paraphrased - 'it was as strong as a few hurricanes I have been in Florida. My truck was rocking!' He was impressed with the wind and the forecast so I was happy : )

Thankfully the wind was from the WSW and the fire was protected from the worst of it on the lee of the ridge. - Carl Cerniglia - NWS Tucson IMET. 

I have been to fires across the Western United States, but never one in my immediate local area. It is a different feeling when it is your home and your mountain where you hike/recreate. However, the mission does not change regardless of location and the work continues. I worked on this fire as an Air Resource Advisor (ARA) and IMET for much of the incident and this was my view when I ended my work day. My girlfriend is a Fire Prevention Officer for the Coronado National Forest and worked the fire as well, so we were in a constant state of stress and concern during the incident. At the conclusion of the incident we breathed a sigh of relief, but was exhausted. We are forever grateful to everyone that helped with this incident to preserve the forest and desert landscapes we love and call home. - Jeremy Michael, NWS Tucson IMET/ARA.

This was the first time I have ever issued a local Severe Thunderstorm Warning for an incident. This was the picture I quickly snapped as evacuating to a safe and sturdy location after the radio alert briefing. Blowing ash, dust, and severe winds quickly ensued. I immediately turned my attention to the potential for debris flows as Agency Administrators were huddled around me while briefing them of the threat. Thankfully no significant flooding was reported with only minor tree damage and hail up to nickel size. - Jeremy Michael NWS Tucson, AZ IMET/ARA.