As we come into the north-flowing warmth of the North American spring, the impacts of snow drought and heat dome are prepping wildland fuels for what may be a transition to a “super” El Nino.
Yet it is spring, and reading the North American Seasonal Fire Assessment and Outlook for April through June we note that there is something assuring in the calm, expert insights from nearly a dozen analysts from Servicio Meteorológico Nacional (Mexico), the National Interagency Fire Center (United States) and Natural Resources Canada.
This is not to downplay a winter with extraordinary fire activity — for the U.S., the latest national Situation Report counts 22,000 fires year-to-date (150 percent of the 10-year average) and nearly 1.8 million acres burned (190 percent of average).
Moving into the spring, the Seasonal Fire Assessment identifies numerous regions likely to see above-normal fire activity (and some will be very active), but overall there are broad regions enjoying what may be a truncated spring green-up with the potential to transition too quickly into what many fear will be a quite literal (and potentially tragic) barn-burner of a summer.
In the Seasonal Fire Assessment, released April 15, the authors observe that what North America faces is both global and as local as the dry dirt under our feet: “The critical factors influencing significant fire potential for this outlook period are global climate patterns related to sea surface temperatures, particularly in the Pacific Ocean, and large scale, longer-term soil moisture deficit.”
It’s the soil moisture deficit that’s a challenge to overcome … with the current Drought Outlook for mid-April highlighting the drought in the US West (with growing dry holes in the central Rockies) and in much of the Southeast.
A 12-week drought animation, closing out on April 14, illustrates the expanding deficit, with at least 70% of the U.S. in drought since the beginning of February.
This drought impact has already been noted in a Fuels and Fire Behavior Advisory for the Southeastern United States, issued April 16 for the southern Appalachians, Piedmont and coastal Southeast — basically, a swath from New Orleans to Cincinnati, Ohio to Washington, D.C., to Florida.
The Southern Area analysts caution that “normal” fire conditions may not moderate the extraordinary dry fuels …
Typical fire weather thresholds may not apply when record high fire danger and record heat align – critical conditions may occur with RH 5% above and winds 5 mph below regional thresholds
Do not be fooled by fuels that appear to be green – fire will spread readily under current conditions
Back to the North American Seasonal Fire Assessment, we note that the above normal activity for the southeast U.S. is also appearing in Mexico’s active fire season.
As summarized by the analysts: “Considering current temperature and precipitation patterns, national drought status, and seasonal forecasts, wildfire activity is expected to escalate across most of Mexico during April and May.”
While they note that spring is “projected to be comparatively less warm due to slightly above average rainfall, which will enhance soil moisture and effectively modulate fire intensity.” With the potential for warmer and moister conditions, they also note the impacts of variability: “the transitioning to ENSO-neutral in May keeps the potential for extreme dry or wet events … a highly unstable and wetter than normal spring is expected compared to previous years, though significant heat will still characterize the season.” Moving into June, fire activity will move north into northern Baja and moderate in the south.
Moving north, the U.S. is likely to parallel the seasonal north-ward green-up, with notable exceptions:
In June, above normal potential will continue in much of the Southwest, while also expected into much of southern Nevada, southern Utah, and the Colorado West Slope. Above normal potential will also expand across much of northern California and the Inland Northwest. In the Southeast, above normal potential is forecast to persist for South Georgia and Florida, while also expected for portions of East Texas and Louisiana.
The western U.S., is expecting a summer-long impact from the dire lack of snow water equivalent (SWE). The combination of a record snow drought followed by record heat dome has left key watershed regions at 9 to 53 percent SWE of normal.
Canada, however, is likely to benefit from a winter snowpack more robust than the U.S., with fire activity increasing in June — though the analysts note “minimal skill” in some of the outlooks, due to the movement from La Niña and into ENSO-neutral conditions.
For June, much of the country [Canada] shows at least a moderate probability of positive temperature anomalies, but these are particularly evident throughout British Columbia and Labrador as well as areas surrounding Hudson’s Bay. Precipitation outlooks offer no clear signal and minimal skill. That, combined with likely ENSO-neutral conditions supports higher fire potential in June throughout British Columbia and areas surrounding James Bay, west of Hudson’s Bay, and extending into the eastern Northwest Territories. Near-normal activity is expected in the rest of Canada in June.
After June, the impact of ocean-warming may lead us into a “super” El Niño, with the El Niño outlook moving from moderate to strong to very strong over the next few months.
Beginning in June, there is 79 percent likelihood of some stage of El Niño ocean warming. By August, the probability rises to 90 percent, with 63 percent likelihood of Moderate to Very Strong conditions. For much of the U.S, outlooks suggest warmer than normal temperatures and variable precipitation effects. An analysis from Severe Weather Europe expands the impacts and predicts “global weather disruption” for 2026 into 2027.
For now, the North American seasonal fire assessment maps offer a view of our immediate fire future, April through June. Of note: in the three months of continent-wide fire assessments, only two relatively small regions in Canada indicate below-normal fire activity.
