November Wildfire Potential At or Returning to Normal

As the ‘typical’ fire season comes to a close, the National Interagency Fire Center is forecasting below-normal, normal, and returning-to-normal autumn conditions across the U.S.

The only area not already at or below normal fire potential is Southern California’s coast which remains in a drought but is predicted to return to normal by the end of the month.

 Image by NIFC – Predictive ServicesNovember 2015 Fire Potential

So far the fall season has brought a few significant rain events coupled with high tropical activity in the Eastern Pacific. Heavy rain fell in Texas and in the Southeast U.S. leading to below-normal fire potential in those now-soggy areas. The approaching El Niño has a high probablity of continuing into the Spring of 2016 and keeping conditions wet in the Southern U.S. and most notably in drought-stricken California where normal fire potential is predicted to resume for the next three months. 

The full NIFC Fire Potential Outlook can be found here.

 

Quite the Air Show for Small Gibraltar Fire

Yesterday’s Gibraltar Fire near Montecito Peak in Santa Barbara County must have had fire officials worried. Ten air tankers and a DC-10 dropped a reported 85,000 gallons of fire retardant around the small ridge top burn. 

Some majestic photos were floating around twitter and news sources yesterday with several air drops and helicopters putting on an air show near Montecito Peak. Past major fires in that area coupled with strong winds and incoming Santa Ana conditions forced the fire’s unified command to unleash an aerial assault to keep the fire from getting established in the mountains above Montecito. 

 

retardant_gibraltar.jpgImage from USFS

Aerial photos showed almost as much retardant on the ground as burned area. The Fire is currently being reported at 40 acres and 50% contained. Crews are expected to stay on scene through this evening to strengthen containment lines and to continue with the mop-up process. All evacuation advisories were lifted at 8am this morning as forward progress was stopped mid-afternoon on the 29th.

 

What Happens To Plants After A Wildfire?

News regarding large wildfires typically covers the location of the fire, the size of the fire, and the fire’s impact on people and property. With the possibility of hundreds of homes destroyed, thousands of people displaced, and millions in damaged property, it’s no wonder much of the media’s attention of large wildfire events is focused on what happens DURING a fire.  But what happens after a wildfire is out?  Or specifically, what happens to plants and vegetation after a wildfire burn? Does the ground remained scorched, forever void of life like some scene out of Mad Max?

The truth is wildfire has helped to shape California’s vegetative landscape for thousands of years. It affects the kinds of plants growing in a particular area, their abundance, size, health, and lifespan. The fire kills some plants, rejuvenates others, and some plants may even need fire in order to thrive.

Some areas in Southern California have plants with leaves naturally coated in flammable oils that encourage a fire to spread. The heat from the fire causes their fire-activated seeds to germinate and the young plants can then take advantage of the fact that the other surrounding plant life was destroyed in the fire. The cones of the Lodgepole Pine are sealed with a resin that is melted away by fire, which then causes the seeds to be released. Other plants have smoke-activated seeds which function in a similar manner. Some trees, like the giant sequoia tree, rely on wildfires to make gaps in the vegetation canopy so that sunlight can reach the forest floor allowing their seedlings to grow.  

This map (courtesy of the Department of Agriculture, Forest Service) shows the effects of wildfires on plant life in various regions of the US. The color coding shows the different ecosystem types and the frequency of fire (and types of fire) that allow those plants to thrive.

Some key definitions (courtesy of the Department of Agriculture):

Understory Fire

A fire in forests or woodlands that is not lethal to the dominant, overstory vegetation and thus does not change stand structure substantially. Most (75%) of the dominant vegetation survives.

Mixed Severity Fire

A fire that causes partial (26-75%) replacement of the upper canopy layer.

Stand Replacement Fire

A fire that kills all or most of the living upper canopy layer and initiates succession or regrowth.

Recent Surge in Texas Fire Activity Despite Historic Rainfall in May

Though Texas saw record rainfall in the month of May, fire season is still in full swing. South Central Texas in particular has seen a significant surge in wildland fires. In the last seven days, there have been 268 fires reported with 12,911 acres burned. The largest of these fires was the Hidden Pines Fire in Bastrop County which consumed 4,582 acres and destroyed 68 homes.

Why has Texas seen an increase in fire activity in recent weeks? A wet spring brought significant grass growth to much of the region. Since June, temperatures have been normal to slightly above normal, while relative humidity levels have been below normal. This has allowed new grass growth to become very dry and prone to ignition. Dry grass can be ignited by the smallest of heat sources such as vehicle exhaust pipes, emergency flares, and cigarettes. Once grass has started to burn, it can rapidly spread to surrounding vegetation and structures. These fast moving grass fires become difficult for firefighters to contain due to their rate of spread and unpredictability. Fortunately, weather forecasts are predicting cool and rainy conditions for the next several days, allowing firefighters a much needed break.

https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/06/01/record-breaking-may-rainfall-in-texas-and-oklahoma-by-the-numbers/

NIFC’s Wildland Fire Outlook

At the start of each month, the National Interagency Fire Center (NIFC) produces a 3 month significant wildland fire potential and weather outlook for the entire country. The Wildland Fire Potential map shows a national picture of the expected trend for fire activity and growth based on previous fire history and current weather predictions. This information is used by Fire Managers to determine staffing levels, anticipate large fire growth, and prepare for the need for pre-positioning out of area resources.

month1_outlook.pngBased on the current forecasts from NIFC and the drought conditions, October will likely bring above normal potential for wildland fires in California. This time of year also brings the potential for Santa Ana wind events over Southern California. Much of the nation will see normal to below normal fire potential, due in part to the significant rains that have impacted much of the country in the last week.

To see the NIFC Significant Fire Potential predictions for the months of November and December, click the link below.

http://www.predictiveservices.nifc.gov/outlooks/monthly_seasonal_outlook.pdf

Sundowner Winds and Their Impact on Fire Behavior

A sundowner wind is an offshore northerly Foehn wind that occurs near Santa Barbara, California. The winds surface when a ridge of high pressure is directly north of the area, and they blow with greatest force when the pressure gradient is perpendicular to the axis of the Santa Ynez Mountains which rise directly behind Santa Barbara. These winds often precede Santa Ana events by a day or two, as it is normal for high-pressure areas to migrate east, causing the pressure gradients to shift to the northeast.

 

Sundowner winds are dried and heated by the warm inland valleys and deserts. As narrow canyons and valleys compress the winds, they become stronger and overpower the diurnal winds. Firefighting efforts during a sundowner wind event can become extremely difficult. The Jesusita fire in May 2009 burned 8,733 acres and destroyed 80 homes while damaging 15 more. Most of the destruction occurred while sundowner winds pushed the main fire through populated areas. The Painted Cave Fire during June 1990 rapidly grew to 5,000 acres, destroying 427 buildings and killing 1 civilian.

 

September a Historic Month for Wildfire in California

Containment of three major fires nears after a tumultuous and historic month for wildfires in California.

Incident management teams on all three fires have made great progress of late on containing the Butte, Rough, and Valley Fires. This month the Valley Fire near Clear Lake has destroyed 1,958 structures while the Butte Fire near Jackson has taken out another 818. In terms of structures lost, that makes them number 2 and number 5 respectively since 2003 in California. Only the 2003 Cedar fire in San Diego County has destroyed more. As the Rough fire continues to gain acreage burned, it has moved up to number 13 all-time in California in terms of acreage burned at 151,493. 

Three large fires nearing containment

According to the National Interagency Fire Center, California’s fires have burned 818,946 acres so far this year. These three are over one-third of that total.

 

As Autumn Looms, So Does the Threat of Santa Ana Winds

Annually, the onset of the fall and winter seasons brings the highest chance for Southern California’s famed Santa Ana winds.

Typically Santa Ana air mass conditions are brought on by high pressure inland and lower pressure off the Pacific Coast which brings very hot and dry weather along with strong, down-slope winds.  In the past, the critical fire weather conditions that accompany Santa Ana winds turn the typically dry chaparral of Southern California into explosive fuel.  Some of the country’s costliest fires in history have taken place in these conditions.

Santa Ana Winds derive from High Pressure in the Great Basin

Interestingly, this year meteorologists are expecting an El Niño cycle to begin affecting the area with rains by November.  In the meantime, as the tropical air mass that has brought this summer’s rain gives way to autumn’s Pacific air mass, a few Santa Ana events should precede the El Nino’s wetting effect.

 

California Wildfires By the Numbers

It’s been a busy year for California wildfires. To date, The Northern and Southern California Geographic Area Coordination Centers have reported a total of 7,541 fires for 783,968 total acres burned. To put it in perspective, that’s larger than the entire state of Rhode Island… burned.

 Let’s have a look at the previous five years as reported by the National Interagency Fire Center (NIFC):

Year

Total Fires

Total Acreage

2014

7,865

555,044

2013

9,909

577,675

2012

7,958

869,599

2011

7,989

126,854

2010

6,554

109,529

 

The previous five year average was 8,055 fires for 447,740 acres burned. And while California is a bit under the average this year, it’s only mid-September, and US Forest Service officials are expecting to see fire activity until at least November.

 

Fewer fires but more acreage can only mean one thing, larger fires. This year California has seen six fires over 50,000 acres in size, with four of those still actively burning. Again, let’s have a look at the previous five years as reported by NIFC:

 

Year

Fires > 50k acres

2014

3

2013

1

2012

2

2011

0

2010

0

 

The previous five year average was approximately one large fire per year in California. With so many large fires this season, firefighting resources have been stretched thin. Not to mention that California has sent equipment and manpower to other states that have also been impacted by wildfires this year.

Rain Not Always Welcomed Forecast for Wildfire Scorched Areas

As the Valley Fire in Northern California continues to burn, the forecasted rain can help and hurt.

The Valley Fire north of San Francisco, CA has burned 70,000 acres and is 30% contained. Active fire and visible flames still cover a lot of the area, and the rain expected today will likely help firefighting efforts to cool and douse these parts of the fire. However, for the areas already scorched by this blaze, like Middletown, with burned, unprotected soil, the rain brings further concerns of landslides and flash flooding.

20150915_ValleyFire

 

Many variables lead to increases in risk for an area for landslides and flash floods. One such consideration is recently burned areas that have little to no vegetation to hold the soil in place and minimize erosion. Another notable fire in Northern California is the Butte Fire (71,780 acres, 45% contained) near San Andreas which is also in areas of mountainous terrain. This increased slope is another concern after a wildfire when rain approaches.

Images like the one seen above (taken by a RedZone Liaison on the ground near the Valley Fire today) are becoming common as large wildfires continue to burn across the Western US and Alaska this fire season. Many show no signs of being contained until snowfall.