Researchers link smoke from fires to tornado intensity

Some university and federal government scientists have concluded there is a link between smoke generated by vegetation fires in Central America and the intensity of tornadoes in the southeast United States. Their research was funded primarily by the federal government, but if you want a copy of their results it will cost you $38 — rather than making the government funded product available to taxpayers as an Open Access document.

Below are some highlights of their research.

Can smoke from fires intensify tornadoes?

“Yes,” say University of Iowa researchers, who examined the effects of smoke—resulting from spring agricultural land-clearing fires in Central America—transported across the Gulf of Mexico and encountering tornado conditions already in process in the United States.

The UI study, published in the journal Geophysical Research Letters, examined the smoke impacts on a historic severe weather outbreak that occurred during the afternoon and evening of April 27, 2011. The weather event produced 122 tornadoes, resulted in 313 deaths across the southeastern United States, and is considered the most severe event of its kind since 1950.

The outbreak was caused mainly by environmental conditions leading to a large potential for tornado formation and conducive to supercells, a type of thunderstorm. However, smoke particles intensified these conditions, according to co-lead authors Gregory Carmichael, professor of chemical and biochemical engineering, and Pablo Saide, Center for Global and Regional Environmental Research (CGRER) postdoctoral fellow.

They say the smoke lowered the base of the clouds and increased wind shear, defined as wind speed variations with respect to altitude. Together, those two conditions increased the likelihood of more severe tornadoes. The effects of smoke on these conditions had not been previously described, and the study found a novel mechanism to explain these interactions.

“These results are of great importance, as it is the first study to show smoke influence on tornado severity in a real case scenario. Also, severe weather prediction centers do not include atmospheric particles and their effects in their models, and we show that they should at least consider it,” says Carmichael.

“We show the smoke influence for one tornado outbreak, so in the future we will analyze smoke effects for other outbreaks on the record to see if similar impacts are found and under which conditions they occur,” says Saide. “We also plan to work along with model developers and institutions in charge of forecasting to move forward in the implementation, testing and incorporation of these effects on operational weather prediction models.”

In order to make their findings, the researchers ran computer simulations based upon data recorded during the 2011 event. One type of simulation included smoke and its effect on solar radiation and clouds, while the other omitted smoke. In fact, the simulation including the smoke resulted in a lowered cloud base and greater wind shear.

Future studies will focus on gaining a better understanding of the impacts of smoke on near-storm environments and tornado occurrence, intensity, and longevity, adds Carmichael, who also serves as director of the Iowa Informatics Initiative and co-director of CGRER.

Paper co-authors are Scott Spak ofthe UI Departments of Urban and Regional Planning and Civil and Environmental Engineering; Bradley Pierce and Andrew Heidinger of National Oceanic and Atmospheric Administration Satellite and Information Service Center for Satellite Applications and Research; Jason Otkin and Todd Schaack of the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison; Arlindo da Silva of NASA Goddard Space Flight Center; and Meloë Kacenelenbogen and Jens Redemann of NASA.

The paper “Central American biomass burning smoke can increase tornado severity in the U.S.” can be found online [for a fee of up to $38].

The research was funded by grants from NASA, U.S. Environmental Protection Agency, National Institutes of Health, National Oceanic and Atmospheric Administration, and the Fulbright-CONICYT scholarship program in Chile.


Wildfire smoke map, September 18, 2014

Smoke map, 9-18-2014

Map showing the distribution of smoke from wildfires, September 18, 2014. The darkest plume is from the King Fire west of Lake Tahoe in California. Map courtesy of Weatherunderground. (click to enlarge)

When the King Fire in California ran 16 miles for an additional 52,400 acres on Wednesday, it put up a very large plume of smoke that is affecting air quality in Boise, Idaho this morning.


Smoke maps, September 15, 2014

Smoke map

Smoke map, northern California, 9-15-2014

Here are two maps showing the distribution of smoke from wildfires. The one above of northern California is from NOAA, and I believe it is a forecast, looking ahead several hours and takes into account the major expansion of the King Fire east of Placerville Monday afternoon, which is the larger plume.

The map below is from Weatherunderground, showing the western United States.

Smoke map western US

Smoke map, western US. Weatherunderground.


Smoke from Happy Camp Complex continues to plague residents of northwest California

Smoke from the Happy Camp Complex of fires

Smoke from the Happy Camp Complex of fires in northwest California as seen from a satellite, September 5, 2014. The Smog Blog.

The Happy Camp Complex of fires in northwest California continued to expand on Friday, adding another 5,660 acres to bring the total up to 88,546 acres. The Incident Management Teams are calling it 25 percent contained. Another spot fire across the Klamath River and Highway 96 burned about two acres before it was knocked down north of the intersection of the highway and Scott River Road.

The Happy Camp area is infamous among wildland firefighters and locals for the inversions that trap smoke and keep it from dispersing. Some firefighters, after spending a couple of weeks in the polluted air, return home with respiratory problems that can linger for weeks or months.

wildfire Smoke map, Sept 6, 2014

Smoke map, Sept 6, 2014. Weatherunderground.

Smoke map, September 5, 2014. for northern California

Smoke map, September 5, 2014. for northern California. Source: California Smoke Information.

The air quality agencies recognize the problem, of course, but there is little they can do about it other than inform the public about how bad it is. The chart below warns that during the three day period five communities had or will have “unhealthy” air to breathe for at least one day: Seiad Valley, Happy Camp, Somes Bar, Orleans, and Weitchpec. Two others, Hoopa and Willow Creek, were in the “Unhealthy for Sensitive Groups (USG)” category.

Air quality forecast for northern California

Air quality forecast for northern California. “USG” means “Unhealthy for Sensitive Groups”. Source: California Smoke Information.

The California Smoke Information website had more details about the wildfire smoke conditions, posted on September 6, 2014:

Yesterday — Winds pushed smoke to the Southwest which impacted the communities of the lower Klamath, Salmon, and Trinity River drainages. Smoke pooled into the valleys at night and kept smoke concentrations high. The forecast change in wind direction was delayed and has yet to occur.

Today — Smoke is predicted to travel southwest down the Klamath and Salmon River drainages in the morning hours. By afternoon, smoke will change directions and head eastward to the Scott and Shasta Valleys. Smoke will pool in valleys and drainages overnight.

Tomorrow — Weather will be similar to the previous day. Smoke is forecast to pool into valleys and drainages with low dispersion. Communities to the west of the fires may experience improved conditions as an onshore flow pushes the smoke slightly westward.