Education
Fire Climate 101
Six concepts that explain the western fire crisis, each backed by a live dataset on this site. Written for classrooms, newsrooms, and anyone starting from zero. Free to use and adapt with attribution.
Teachers: this page prints cleanly as a handout, and every concept links to an interactive chart students can explore with current data.
Snowpack is the starting condition
Western summers are dry by design; the water that keeps forests moist into July falls as winter snow and melts slowly through spring. Scientists measure it as snow water equivalent (SWE), the depth of water the snow would produce if melted, at over 1,800 automated SNOTEL stations. When April 1 SWE is low, the landscape starts its summer drier and earlier. In 2026, 1,012 of 1,570 corridor stations set all-time April 1 record lows.
Explore the snowpack charts on the dashboard →Heat pulls water out of the landscape
Vapor pressure deficit (VPD) measures how strongly the atmosphere pulls moisture from soil and plants; it rises steeply with temperature. Western summer temperatures have risen about 2.2°F per century, and annual VPD correlates with area burned at r = 0.70 over the last four decades. Drier air means drier fuels, and drier fuels mean larger fires.
See the 41-year VPD vs. burned-area panel →The two forces compound
Low snowpack means the fire season starts earlier; heat and VPD mean fuels dry faster and deeper once it does. The result is not simply more fire but longer, hotter seasons (Westerling et al. 2006; Abatzoglou & Williams 2016). The modern era (2000–present) burns about 4.2 times the area of the suppression era (1950–1990) across the western US.
125 years of fire history, charted →ENSO tilts the odds
El Niño and La Niña, the warm and cool phases of the tropical Pacific, shift the winter storm track. El Niño winters tend to leave the Pacific Northwest warmer and drier (less snowpack, longer next fire season) and the Southwest wetter (short-term relief, then a heavy fine-fuel crop). ENSO doesn't ignite fires; it loads the dice a season ahead.
Our monthly El Niño and the Fire Corridor column →A century of suppression stockpiled fuel
Dry western forests historically burned in low-severity fires every 5–25 years, many set deliberately by Indigenous nations. A century of putting every fire out let fuels accumulate, so the fires that escape today burn hotter and larger, the “fire paradox.” The measured fix is mechanical thinning followed by prescribed fire, which cuts subsequent fire severity by more than 60%.
The evidence review: what actually stops a megafire →Smoke is the wider harm
Wildfire smoke's fine particles (PM2.5) penetrate deep into lungs and travel thousands of miles; smoke is estimated to kill more people each year than flames do. Understanding AQI categories, and how to build a clean-air room, is fire-climate literacy too.
Air quality, health effects, and protective actions →Going deeper: our Methods page documents every dataset and model limitation; the Climate Arguments handbookaddresses common misconceptions; and for general climate science beyond fire, NOAA’s former climate.gov team continues excellent explainer work at climate.us. Key papers: Westerling et al. (2006), Science; Abatzoglou & Williams (2016), PNAS; Davis et al. (2024), Forest Ecology and Management. Questions or corrections from educators: contact@pnw-firemap.org.