Mars Warming Due to Dust Storms, Study Finds

This study discusses the dusty tornadoes, known as dust devils, compounded with strong winds that have darkened Mars' surface allowing it to become more susceptible to absorbing the sun's rays and heat. NASA researchers have created a computer model of winds on Mars, which enables them to see how the winds may impact the planet's climate. In the 1970's, wind storms caused shiny dust particles to redistribute around Mars, exposing its dark surface below. The dark surface occasionally heats the surface up enough to cause the previously discussed dust devils. This climate on Mars differs from Earth's, which is more greatly influenced by clouds.

http://news.nationalgeographic.com/news/2007/04/070404-mars-warming.html