Colorado extreme rainfall and flood event of 2013

Like many people around the world I watched and followed the astonishing rainfall and flood events in Colorado in September this year that resulted in at least 10 deaths, damaged some 18,000 homes, caused the evacuation of more than 10,000 people, washing away roads and bridges and isolating communities for a time. The rain and flood event is estimated to have caused $2 billion worth of damage.

The extent of the rainfall was unprecedented in meteorological records that stretch back a little more than 100 years. The extreme rainfall event has been described as a 1 in 1,000 year event. An Extremely rare combination of weather factors combining to produce the event.

Climate change however stacks the dice in several ways in increasing the probability of this event occurring in the future. A primary contribution is the increase in atmospheric capacity to carry water vapour which scientists have worked out to be 6 per cent to 7.5 per cent for each degree Celsius in average global warming. By the end of this century with average global surface temperatures projected to increase by 4 to 5 degrees with current business as usual scenarios, the atmospheric carrying capacity may be an extra 30 per cent, making extreme precipitation events like the Colorado event much more likely to occur.

Wildfires set new destructive records in Colorado and New Mexico due to climate change

High temperatures, high winds and low humidity are contributing to extreme fire weather across the US southwest. In Colorado the Black Forest fire burning north east of Colorado Springs has become the most destructive fire on record for the state destroying at least 379 homes and killing two people. Over the border the Whitewater Baldy Complex fire in the Gila National Forest has become the largest wildfire in New Mexico's recorded history. For several years scientists have indicated that Climate change is a primary cause driving the increase in the length of the fire season, the frequency and intensity of wildfires.

Reports from Colorado confirm that the Black Forest fire has so far burned 15,700 acres; 38,000 people and 13,000 homes evacuated; with the fire only 5% contained. 379 homes have been destroyed and a further 9 damaged. The damage exceeds the record destruction last year from the Waldo Canyon Fire which destroyed nearly 350 homes and also killed two people. Another Colorado wildfire near Royal Gorge has burnt 3,100 acres, destrying 20 structures and is just 20% contained.

Over the border in New Mexico the Whitewater Baldy Complex fire continues to burn in the Gila National Forest. It is the largest wildfire in New Mexico's recorded history. Started by a lightning strike on May 15th 2013, the fire has burned almost 280,000 acres and is assessed as only 37% contained one month later in mid June. High temperatures, low humidity and moderate winds continue to feed the fire. Fire fighters are focussed on containing the southern boundary of the fire. Costs of fighting this blaze have now exceeded $22 million.

Climate change is driving the increased destruction of wildfires with US Forest Service Chief Thomas Tidwell warning of more extreme wild fires in testimony to the US Senate Energy and Natural Resources Committee last week.

In 2012 wildfires burned a record 9.2 million acres in the U.S., with this year also likely to set exceptional fire records.