Fire Ignition Potential Definition


Number of days annually with a High Fire Danger rating for Forested and NonForested landcover at time steps: historic (1991-2020 normal), last four years (e.g. 2018-2021), near term NowCasts (i.e. short term future forecasts ~30-60 days) and climate projection normals (2031-2060, and 2061-2090) across 11 Global Circulation Models (GCM) and an ensemble mean across all GCMs by Representative Concentration Pathways (RCP) climate scenarios 4.5 (low emission) and 8.5 (high emission).

A High Fire Danger rating was defined as having a fire ignition potential >= to the 84th percentile for forest and non-forest water balance deficit value across fires greater than 405 ha within the Monitoring Trends in Burn Severity database between 1984-2021 in the Southern Rocky Mountain Ecoregion. For additional details on the ignition model see Thoma et. al. 2020 at https://doi.org/10.1016/j.gecco.2020.e01300. Southern Rockies Fire Ignition model version 2.0 from Steve Huysman has been applied for details see: https://huysman.net/research/fire/southern_rockies.html#Fire_Danger_Model

Data Sources Ignition Potential: Historic and Now Cast water balance deficit data is from the Florissant GRIDMET Station. Future projection data spatially coincident with the Florissant Grid Met Station was obtained from NPS Water Balance data version 1.5 at: http://www.yellowstone.solutions/thredds/catalog.html.

Freeze Thaw Days Definition


Number of freeze thaw days of the recent past compared to the future projected number of freeze thaw days under RCP 4.5 and 8.5 climate scenarios. A freeze/thaw day is defined as having maximum temperature >34.2 °F and minimum temperature <28 °F, see Fraser 1959 at https://doi.org/10.14430/arctic3712.

Black dots depict data from the Florissant Fossil Bed National Park weather station that was bias corrected with gridmet data using the delta method. The black line represents the 30-year mean using gridded climate data from gridmet. Colored dots represent climate projections from the gridded Multivariate Adaptive Constructed Analogs (MACA) data at: https://www.climatologylab.org/maca.html. Each small colored dot represents a prediction from one of 20 Global Climate Models (GCMs) while the large colored dots represent ensemble means of all 20 GCMs.

Bias correction was the difference in average annual normal for 1990-2020 at Florissant Fossil Bend National Park weather station relative to the coincident gridmet data. With the difference being used to adjust the weather station average to match the gridmet average. This correction was applied to all weather station data.