The observed lightning record for Interior Alaska suggests that there have been significant increases in lightning activity in the region since 1979. This lightning observation record is very limited in the areas it covers however, leaving large gaps in space and time. Recently published research by AK CASC and Alaska Fire Science Consortium (AFSC) scientists utilizes modern climate data and downscaled climate modeling to suggest that these observations are correct, but may not reflect the true magnitude of the change.

The June to July period marks peak lightning activity across Interior Alaska which was the focus of the research. Though lightning does occur in other parts of the state, and during other times of the year it is this peak lightning period which is of most interest to researchers. “Climatologically, very little lightning occurs along the coasts and on the north slope even during peak months.” states the paper published this June in the Journal of Applied Meteorology and Climatology. Not only is the frequency of lightning strikes higher in this area and time period, but its impact on the fire regime is significant. About 90% of the area burned by wildfire each year in the state burns as a result of wildfires started by lightning.

Using model projections: a specialty of the AK CASC

Downscaled global climate model projections can be applied to lightning prediction to model change as a result of changes in the climate. By modeling lightning strike changes for the same period as the observed record, we can understand where the gaps in observation may lead to incorrect conclusions about the nature of lightning across the state.

White smoke rising from the tundra in front of the Baird Mountains.

Peat, common across the Arctic, is good fuel for lightning-ignited fires such as these near the Baird Mountains.
Photo Credit: Western Arctic National Parklands

Model projections confirm the conclusions of the observed record, and demonstrate an increase in lightning activity for the area. They do, however, suggest that observed increases may be less pronounced than the observed record would suggest. These projections do suggest that increases in lightning activity are likely to continue over the coming decades, leading to a doubling of activity by the end of the century. This better assessment of the past, present, and future of lightning activity is critical for understanding the wildfire patterns so common to this region of the state.

The researchers are careful to clarify though, that lightning is only one of many factors key to understanding the wildfire system. Burn scars from past fires, topography, and vegetation can all impact thunderstorm activity as much as changes in climatic conditions. Additionally other weather conditions such as fire fuel load, are critical to fire researchers and are being actively researched by CASC scientists.

Read the paper in the Journal of Applied Meteorology and Climatology and find out more about the AFSC’s work on their website. To find out more about fire weather, fuel, and wildfire prediction in this CASC article from 2019 or use the Wildfire in Alaska tool developed by the Scenarios Network for Alaska + Arctic Planning (SNAP). The AK CASC, AFSC, and SNAP are all collocated at the International Arctic Research Center at UAF.