California forests hit hard by wildfires in the last decade

About 25 percent of the states’ forestland burned in the last 10 years — more than triple the previous decade

BAe-146 drops Winding Fire
BAe-146 drops on the Winding Fire in Northern California June 18, 2022. InciWeb.

By Jim Schmidt

Of the 32.1 million acres of forestland in California, approximately 2.1 million acres (6.6%) burned in wildfires in the 2002-2011 time period. In the following decade (2012-2021), that figure more than tripled to 7.9 million acres (24.7%).

National Forests in California were particularly hard hit.  10.1% of 12.7 million acres of forestland managed by the USDA Forest Service in California burned in 2002 – 2011 time period.  In the 2012 – 2021 decade that figure increased to 38.8%. Excluding areas that re-burned in the last 10 years, 44.5% of the forestland in California National Forests has burned in the last 20 years.  In contrast, only 22.6% of National Park forestland in the state has burned in the same time period. About 14 million acres of forestland in California are in private hands.  17.0 % of private forestland has burned since 2001.

Forestland acres burned California last two decades
Forestland acres burned by wildfires in California by owner class, 2002 – 2021. Jim Schmidt

The following maps display the forestland areas and the areas that have burned in California in the last two decades. Fires were concentrated in Southern California in the 2002-2011 time period and in Northern California in the last 10 years.

Map, California forestland and wildfires, 2002 - 2011
California forestland and wildfires, 2002 – 2011. Jim Schmidt
Map, California forestland and wildfires, 2012 - 2021
California forestland and wildfires, 2012 – 2021. Jim Schmidt

The article was edited September 7 with revised figures to account for areas that reburned, which account for about 5% of the forestland burned on National Forests in the last 20 years.

Jim Schmidt retired from the Stanislaus National Forest where he worked as a GIS specialist.

Wildfire acres burned to date in United States (outside Alaska) is lower than average

Precipitation, 7 days
Precipitation, during the seven days ending at 11 a.m. MDT August 13, 2022.

It seemed to me that over the last few weeks the wildfire activity has been slower than typical for this time of the year, so I did a little digging. Using historical data from the National Interagency Fire Center and acres burned to date from the August 13 national Situation Report, it turns out that Alaska has burned nearly three times their 10-year to-date average while the other 49 states combined are running 12 percent below the to-date average.

Over the last 10 years Alaska’s average acres burned in a full year is 1.1 million. This year they are at 3.1 million, more than the other 49 states combined. There has been a major increase in Alaska acres burned after mid-August in only 2 of the last 18 years. And it has been fairly quiet there, fire wise, for the last four weeks.

So far this year, fires in the other 49 states have blackened about 2.8 million acres, 12 percent below the to-date 10-year average of 3.2 million. The 49 states typically burn 6.2 million in a full year, so if this year turns out like the average of the last 10, we’re about half done.

The Situation Report does not break out data for Alaska and the other 49 states, so just looking at their 50-state numbers a person would see that the 5.9 million acres burned to date is 27 percent higher than the average of 4.3 million, when actually the +27 percent figure is very wrong for both Alaska and the lower 49 states.

We usually separate Alaska stats because fires in that huge state are managed far differently from the other 49. Most of them are not fully suppressed since they are less likely to endanger people or private property than in the lower 49 states. The second reason is that the fire occurrence is extremely variable, with the acres burned since 1990 ranging, for example, from 43,965 acres in 1995 to 6,645,978 in 2004. Including the Alaska numbers in the total would skew the data for the other 49 states making it more difficult to spot trends.

Wildland fire potential for September, 2022
Wildland fire potential for September, 2022. NIFC.
Wildland fire potential for August, 2022
Wildland fire potential for August, 2022. NIFC.

Estimated TOTAL cost of the Camp Fire was about $422 billion

The Camp Fire, November 8, 2018
The Camp Fire, November 8, 2018. NASA (Joshua Stevens) – NASA Landsat 8.

We often publish statistics about wildfires, such as acres burned, average size, number of fires, and average size by decade. Here are some examples. Others are at an article updated February 2, 2022.

Average size of US wildfires by decadeNumber of wildfires

Bankrate has assembled more data about wildfires in an article titled U.S. Wildfire statistics.

Such as:

A study of the 2018 Camp Fire reveals staggering facts and estimations:

  • Total 2019 claims from the Camp Fire: more than $12 billion
  • Total damage and economic losses: more than $400 billion
  • Total insured losses: estimated between $8.5 to $10.5 billion
  • Toxic debris removal: nearly $2 billion
  • Victim aid: $200 million
States most at risk from wildfires

Bankrate also has wildfire data broken down for each state. It’s an interesting way to spend few minutes, perusing the numbers.

More information about the Camp Fire.

Acres burned in lower 49 states in 2021 was more than average

Eight percent higher than the average of the previous 10 years

Updated Feb. 2, 2022

Total wildfire acres

The number of acres that burned in the United States in 2021 according to the annual report from the National Interagency Fire Center, was more than the average of the previous 10 years. The 6,872,286 acres in the lower 49 states is 8 percent higher than the average of the previous 10 years, and 33 percent above the average in the decade before that, 2001 – 2010.

This is contrary to statements from some fire officials in December who said fewer than average acres had burned. That is only correct if Alaska is counted. When it is, the numbers can be misleading. Alaska is a huge state with a very low population for its size. Many fires there burn far from any structures or private property and are not suppressed. On some fires the only action taken is “point protection,” just keeping a small village or single cabin from burning. A fire can burn hundreds of thousands of acres over a period of months with few if any firefighters assigned.

Alaska acres burned

The burned area in Alaska varies wildly from year to year, for example, about 62,000 acres in 2008 and more than 5,000,000 in 2015. In 2015 more acres burned there than in the other 9 geographic areas combined. (Alaska is it’s own geographic area. Map.) However, so far this year, Alaska has ranked only third in number of acres burned in geographic areas, outranking only the Rocky Mountain and Eastern Areas. Including the Alaska numbers in a calculation of fire activity in the 50 states is misleading and can radically skew statistics.

Fires continue to grow larger

The average size of fires 2021 was the fifth largest in the last 36 years. Since 1984 the six years with the highest average size have all occurred in the last 11 years, according to the available reliable data from the National Interagency Fire Center after 1984.

Average Wildfire Size

The total number of fires is on a downward trend

The number of fires in 2021 was the sixth lowest in the last 36 years.

Number of wildfires

All of the statistics for 2021 are from the annual report for 2021 published by the National Interagency Fire Center. Data from previous years also came from NIFC.

So far the drought is far worse than last year

Drought monitor comparison, 2020 & 2021
Drought monitor comparison, similar dates in 2020 & 2021.

As @NOAANCElclimate pointed out, the Drought Monitor shows that the severity of the drought is far worse than it was at about the same date in 2020. Most of the areas in the 11 western states are in Severe, Extreme, or Exceptional Drought.

So far this year the 49 states outside Alaska have burned almost 2.2 million acres, about the same that burned in all of 2019. The 10-year all-year average for those 49 states is 6.4 million acres. In 2020 9.9 million acres burned in the lower 49 states.

Total Wildfire Acres burned 1985-2020

A year-to-date average would be helpful. The National Situation Report gives a number, but unfortunately it includes Alaska which is extremely variable. Fires there can be very large, burning for weeks or months usually with little to no suppression. In the last 10 years the acres burned in Alaska ranged from 181,169 in 2020 to 5,111,404 acres in 2015, with the higher number being 28 times the lower. In 2015 more acres burned there than in the other 49 states combined. Therefore, a year to date average that includes Alaska is virtually meaningless if you want to draw conclusions about the status of the wildfire season in the lower 49 states.

Alaska acres burned
Alaska Acres burned, 2011 – 2020. Raw data from NIFC, processed by Wildfire Today.

New climate data shows summers in the Western states are warming

The number of acres burned in US wildfires in 2020 (not counting Alaska) was the highest ever recorded since reliable statistics have been available beginning in 1960

Annual Temperature & Precipitation change last 30 years

New climate data analyzed by NOAA shows that during July when the fire season in the West is typically nearing its maximum, the temperatures in the 11 Western states have been rising in recent years. The data from the last 10 years also indicates the amount of precipitation in the Northwest has decreased significantly.

Every 10 years NOAA recalculates the U.S. Climate Normals for the previous 30-year period. Normals act both as a ruler to compare today’s weather and tomorrow’s forecast, and as a predictor of conditions in the near future. They consist of annual/seasonal, monthly, daily, and hourly averages and statistics of temperature, precipitation, and other climatological variables from almost 15,000 U.S. weather stations.

The new annual mean data for 1991 through 2020 shows that most of the U.S. was warmer, and the eastern two-thirds of the contiguous U.S. was wetter, from 1991–2020 than the previous normals period, 1981–2010. The Southwest was considerably drier on an annual basis, while the central northern U.S. has cooled somewhat.

The weather in July has a direct effect on the number of acres burned in Western wildfires. The new data shows the Northwest is considerably drier as a percentage of the previous normal during what is already a dry season.

July maximum temperature change

July precipitation change

The rest of the West is pockmarked with wetter and drier zones. The eastern two-thirds of the U.S. has an indistinct pattern of changes in the precipitation normals. Most of the East also remained near the same temperature levels, except for persistent cooling in the north central U.S. and warming in the Northeast. However, the entire West and lee of the Rocky Mountains and Texas are all considerably (up to 2°) warmer.

Total Wildfire Acres burned 1985-2020

This warming and drying trend in the West shows up in wildfire activity. The number of acres burned in the U.S. in 2020 —  9,941,167 (not counting Alaska) — was the highest ever recorded since reliable statistics have been available beginning in 1960.

Average size of US wildfires by decade

The average fire size by decade is striking, increasing by about 400 percent from the 1980s to the 2010s. Some of that increase could be from the tendency of the U.S. Forest Service and other federal agencies to allow some fires to spread without an aggressive full suppression strategy, allowing an unplanned wildfire to accomplish fuel reduction targets and other objectives. They can do this by using virtually unlimited fire suppression funds and without having to bother with pesky steps like conventional project funding, planning documents, approvals, public input, and environmental compliance required by the National Environmental Policy Act.