It is generally accepted that year-to-year variability in moisture conditions and drought are linked with increased wildfire occurrence. However, quantifying the sensitivity of wildfire to surface moisture state at seasonal lead-times has been challenging due to the absence of a long soil moisture record with the appropriate coverage and spatial resolution for continental-scale analysis. Here we apply model simulations of surface soil moisture that numerically assimilate observations from NASA's Gravity Recovery and Climate Experiment (GRACE) mission with the US Forest Service's historical Fire-Occurrence Database over the contiguous United States. We quantify the relationships between pre-fire-season soil moisture and subsequent-year wildfire occurrence by land-cover type and produce annual probable wildfire occurrence and burned area maps at 0.25-degree resolution. Cross-validated results generally indicate a higher occurrence of smaller fires when months preceding fire season are wet, while larger fires are more frequent when soils are dry. This result is consistent with the concept of increased fuel accumulation under wet conditions in the pre-season. These results demonstrate the fundamental strength of the relationship between soil moisture and fire activity at long lead-times and are indicative of that relationship's utility for the future development of national-scale predictive capability.

<p>Flooding is the most common and costliest global natural disaster, accounting for 43% of all recorded events in the last 20 years and expected to increase the global cost of flooding tenfold by 2030. Satellite imagery has proven beneficial for numerous flood use cases from historical modeling, situational awareness and extent, to risk forecasting. The addition of high resolution, high cadence satellite imagery from Planet Labs PBC has been widely adopted by the flood community, from researchers in academia to private companies in the insurance and financial services. </p><p>Planet Labs PBC currently operates over 200 satellites, comprising the largest constellation of Earth observation satellites. The PlanetScope dataset consists of broad coverage, always-on imaging of the entire landmass by 140+ Dove satellites at 3.7 meter resolution. Complementary to PlanetScope, the SkySat dataset includes 21 high resolution satellites imaging at .50 meter resolution with the ability to image and video any location on Earth via automated tasking commands. This presentation will highlight Planet’s capabilities serving the hydrological science community and cutting-edge flood research and technology.</p>