Preliminary results of this study was highlighted in the December 12th, 1998 issue of the New Scientist Magazine (http://www.newscientist.com/article/mg16021643.900.html): The majority of the circumpolar region is covered by boreal forest. Boreal forest is the second largest biome on Earth (Whittaker, 1975), and therefore an important factor in Earth system studies. Global climate models predict that the largest future changes will happen in the polar regions. This has lead to speculations on the influence of warmer, potentially drier summers of the fire activity in boreal forest regions (Ryan, 1991). Fire frequency and severity changes forest stand composition, which impacts regional carbon storage, albedo, surface roughness and the partioning of latent and sensible heat fluxes (Kasischke et al, 1995). Annually, thunderstorms start fires that burn large areas in the boreal forest. For example, most of the area burned in interior Alaska is by lightning-caused wildfires. Thunderstorm development is a very important factor in the continental boreal forest fire regime through its influences as a fire starting mechanism. Understanding the forcing factors that determine where these storms develop is a vital part of understanding the atmosphere - ecosystems interactions that control the boreal environment. The issues addressed here were originally developed in modeling studies, however, we propose to use remote sensing and geographical information system techniques to validate the ideas. If this study indeed reveals a picture of strong, local factors forcing and controlling thunderstorm development, new perspectives on future fire regimes will be created. Additionally, if landscape heterogeneity and the presence of fire scars are part of a feedback mechanism that promotes convective activity, a strong, enforced fire regime may be a possible result of the predicted warm dry climate. This study is an example of how local factors can influence regional scale circulation patterns for one of the worlds largest biomes, thus having a global influence. A recent study by Skinner et al. (1999) examined the correlation between the 500 mb anomaly and the fire severity in the Canadian boreal forest region, and concluded that the accurate prediction of the future Canadian fire regimes requires identification of the relationships between regional scale climate and fires.