Wildfire smoke shrouds Denver; climate change expected to increase Western fires

Colorado's third largest fire in recorded history, the High Park Fire, shrouded Denver and Fort Collins in acrid smoke Tuesday, causing an increase in emergency room visits related to smoke inhalation. The fire, currently burning fifteen miles west of Fort Collins, Colorado, covered over 43,000 acres (68 square miles) as of Tuesday. Firefighters reported that it was only 10% contained, and was exhibiting "extreme" behavior. A lightning strike triggered the fire on Saturday. While fire fighters try to control the southern edge of the fire, the northern perimeter is burning out of control. Six hundred eighty people and 100 fire engines are working on the ground to contain the blaze, along with air support from air tankers and helicopters. The fire has killed one person, burned 100 structures, and cost $1.6 million to fight so far. An air pollution action day has been declared for Wednesday all along the Front Range of the Rockies, from Denver to Fort Collins, due to smoke from the fire. Air pollution levels from smoke will be unhealthy for sensitive groups.


Figure 1. Fire burns in trees behind homes in the High Park wildfire near Fort Collins, Colorado, on Monday, June 11, 2012. (AP Photo)

Beetles, climate change, and Colorado fires
According to the Denver Post, the High Park Fire is burning in an area where 70% of the trees that have been killed by mountain pine beetles; the insects have devastated forests in western North America in recent years. As our climate change blogger, Dr. Ricky Rood explains, the pine beetle is killed (controlled) by temperatures less than -40°F. This is at the edge of the coldest temperatures normally seen in the U.S., and these cold extremes have largely disappeared since 1990. In Colorado, the lack of -40°F temperatures in winter has allowed the beetles to produce two broods of young per year, instead of one. The beetles are also attacking the pine trees up to a month earlier than the historic norm.


Figure 2. The historical mountain pine beetle (MPB) univoltine life cycle (above calendar arrows and linked by black arrows) and the observed MPB bivoltine life cycle (below calendar arrows and linked by red arrows). Univoltine means one brood per year, and bivoltine means two broods per year. Calendar arrow colors represent monthly temperature regimes: blue for less than 0°C, yellow for 0°-4.99°C, orange for 5°-9.99°C, and red for 10°C and higher. From Mitton and Ferrenberg, "Mountain Pine Beetle Develops an Unprecedented Summer Generation in Response to Climate Warming". This figure appeared in Dr. Ricky Rood's blog, "A Hot Day's Night: The Beetles".

A letter from the field in Colorado
Our climate change blogger, Dr. Ricky Rood, is in Boulder, Colorado this summer, and had this report on the fire Tuesday:

Saturday morning Iz and I were driving along 95th Street to Longmont to the Fairgrounds. We saw the initial plume; Iz said, "Looks like a volcano." At that time it was Colorado clear, with blue skies. The plume got to the top of its ascent and kicked off a little convection that looked like cauliflower. For the next few hours you could see the fire grow by the trunk of the plume getting thicker. It mostly blew to the east, with an occasional white cloud topping. It seemed to double in size every couple of hours.

By Sunday, the smoke was spreading all over the state. We had a couple of cool days with a northerly component in the wind. It filled up the sky, here, with haze - most of the day could not see Long's Peak. Part of the day couldn't see the foothills, say Flagstaff Mountain, which is about 8 miles away. Even with the wind moving around to the south, it's remained hazy. Today it has smelt of campfire-like smoke most of the day. Woke up sneezing. There is fine dust drawn to my computer screen and key board, which is at this point simply dirty. The dogs seem a little crazy.

It's not as acrid as the much closer Fourmile Fire a couple of years ago, but for some reason, it's the most dramatic fire I have experienced, perhaps because of the explosive nature of it. Tankers and helicopters fly over all day; they must stage from somewhere south of here. The tanks on them look hopelessly small compared with the fire, but they say, today, they finally made progress. The drought or drought potential is currently stunning, and we expect a lot of fire this year. Water only flowed in our irrigation ditch for four days before we lost priority.

There is a very nice figure in a local magazine, YS, that shows the percentage of snow pack compared with normal. We are South Platte - mid-May at 19 % normal, and not the worst in the state. Really, a nice little article in YS about how to predict a drought. Last year was nearly record wet. Right now this is setting up to be worse than the 2002 drought, which the article says was a 300 year drought. If true, then we had two 300 year droughts 10 years apart--some of our readers should be able to work on that as an attribution problem. The largest fire in Colorado history, the Hayman, was during the 2002 drought.

New Mexico's massive Whitewater Baldy Complex fire continues
The largest wildfire in New Mexico recorded history, the Whitewater Baldy Complex, continues to burn in the Gila National Forest. The lightning-sparked fire began nearly a month ago on May 15th, is 37% contained, and has devoured almost 280,000 acres (438 square miles.) Though fire weather advisories are not in effect in the region, the humidity is extremely low--humidity values of 6% were reported yesterday afternoon in Reserve, New Mexico, inside the burned area. Afternoon winds are expected to remain moderately strong, around 15 mph, over the next few days, as firefighters focus on keeping the southern edge of the fire from spreading. The fire has cost $22.6 million to fight so far.


Figure 3. The Whitewater Baldy Complex fire seen on our wundermap with the fire layer turned on. The red region outlined in yellow is the active fire perimeter.

Western U.S. wildfires expected to increase due to climate change
Expect a large increase in fires over much of the globe late this century due to climate change, says research published this month in the Journal Ecosphere. Using fire models driven by output from sixteen climate models used in the 2007 IPCC report, the researchers, led by Max Moritz of UC Berkeley, found that 38% of the planet should see increases in fire activity over the next 30 years. This figure increases to 62% by the end of the century. However, in many regions where precipitation is expected to increase--particularly in the tropics--there should be decreased fire activity. The scientists predicted that 8% of Earth will see decreases in fire probability over the next 30 years, and 20% will see decreases by the end of the century. The models do not agree on how fire danger will change for a large portion of the planet--54% for the period 2010 - 2039, and 18% for the period 2070 - 2099. Six key factors were found to control fire probabilities in the models. Most important was how much vegetation there was (NPP, Net Primary Productivity). Three other factors, about half as important, were precipitation of driest month, mean temperature of warmest month, and the difference between summer and winter temperature. Two other minor factors were mean temperature of wettest month, and annual precipitation. The authors found that future fire occurrence appears to primarily be a function of available moisture in many areas, and that the expected global increase in temperature of 3.5°C used in the models will not become the single dominant control on global wildfire. In the U.S., the regions most at risk of increased fires are the tundra regions of northern Alaska, and the West, with Arizona and Colorado at particularly high risk.


Figure 4. Predicted fractional change in fire probability for the period 2010 - 2039 (top) and 2070 - 2099 (bottom) for the average of sixteen climate models used for the 2007 IPCC report. For the 2010 - 2039 period, the models agree that 8% of Earth will see decreases in fire probability, 38% will see increases, and the models are too uncertain to tell for the other 54%. For the 2070 - 2099 period, the models agree that 20% of Earth will see decreases in fire probability, 62% will see increases, and the models are too uncertain to tell for the other 18%. Image credit: Climate change and disruptions to global fire activity, Moritz et al., 2012, from the journal Ecosphere.

Rare tornado hits Venice, Italy
A tornado hit Sant'Erasmo island in the lagoon surrounding Venice on Tuesday, ripping the roofs off of at least 12 buildings. No injuries were reported. The Capital Weather Gang has more videos and information on the event. Tornadoes are not unheard of in Venice; a strong one hit the city in 1970, killing 30 people.


Video 1. A waterspout/tornado in the Venice Lagoon on June 12, 2012.

The Atlantic is quiet
There are no threat areas to discuss in the Atlantic today. The NOGAPS and GFS models are predicting formation of a broad area of low pressure in the Western Caribbean early next week, and we will have to watch this area for development. The waters offshore of North Carolina may be another region to watch, over the next few days, along the edge of a cold front that has moved off the U.S. East Coast.

I'll have a new post Thursday or Friday.

Jeff Masters and Angela Fritz