Tornado tracker: live severe weather map and tornado alerts

Modern tornado detection runs on three parallel systems that verify one another. Doppler radar detects rotation within thunderstorms by measuring the frequency shift of returned radar pulses from rain and debris moving toward and away from the antenna. A strong rotational signature — called a mesocyclone — triggers an automated alert and prompts forecasters to issue a tornado warning before a funnel is even visible. The 2012 nationwide upgrade to dual-polarization radar added a second dimension: sending pulses both horizontally and vertically to distinguish rain from hail, and crucially, to detect the lofted debris signature that confirms a tornado is already on the ground.

Storm spotters — trained volunteers coordinated by the National Weather Service — provide the ground truth that radar cannot. A spotter's report of a confirmed tornado on the ground allows NWS forecasters to issue a tornado warning with high confidence and clear, specific language. The national spotter network, called SKYWARN, has over 290,000 trained members.

The warning chain runs from the NWS through the Emergency Alert System (EAS) — which interrupts radio and TV broadcasts — and Wireless Emergency Alerts (WEA), which push notifications to cell phones in the affected polygon without requiring any app. Average lead time for tornado warnings has grown to roughly 13 minutes, up from near zero in the 1970s. The persistent challenge is false alarms: approximately 75% of tornado warnings are not followed by a tornado reaching the ground. This ratio erodes public trust over time, but meteorologists universally argue every warning must be treated as real — the 25% that verify include the events that kill people. See our hurricane tracker for companion severe weather monitoring.

The traditional mental map of U.S. tornado risk centered on a north-south corridor — the Texas Panhandle through Oklahoma, Kansas, and Nebraska — where Gulf moisture clashing with Rocky Mountain drylines creates near-perfect supercell conditions. This region, informally called Tornado Alley, remains prolific. But a decade of peer-reviewed research has documented a consistent eastward and southward migration of tornado activity toward the Southeast.

The Mississippi, Alabama, Tennessee, and Arkansas region — sometimes labeled "Dixie Alley" — now accounts for a growing proportion of violent tornado events and the majority of tornado fatalities in years with major outbreaks. The reasons compound dangerously: the Southeast has denser population distributed across smaller towns and rural areas; thick forest cover blocks sightlines, so residents often cannot see a tornado until it is within a mile; nighttime tornadoes are significantly more common (over 35% of Southeast tornadoes touch down between 6 pm and 6 am, when people are asleep and outdoor sirens go unheard); and manufactured housing — which offers virtually no structural protection — houses a larger share of the population than in the Plains.

The underlying drivers of the shift are still debated. Researchers have proposed changes in Gulf of Mexico sea surface temperatures, shifts in the position and behavior of the jet stream, and altered moisture transport patterns as contributing factors. What is not debated is the policy implication: communities in the Southeast face tornado risk with less "tornado culture" — fewer safe rooms per capita, less practiced shelter behavior, and less institutional knowledge built up over generations of living in the traditional tornado belt. The global disaster tracker documents confirmed tornado events as they are reported.

The Enhanced Fujita (EF) Scale, introduced in February 2007, replaced the original Fujita Scale to more accurately match estimated wind speeds with the damage surveyors actually find. Rather than assigning wind speeds from theory, the EF Scale is built on 28 damage indicators — specific structure types from small barns to high-rise buildings — and for each indicator, eight degrees of damage that carry wind speed estimates derived from engineering analysis of real tornado damage surveys.

EF0: Light damage. Branches broken off trees, shallow-rooted trees pushed over, some damage to gutters and chimneys. The majority of all tornadoes that touch down are EF0.

EF1: Moderate damage. Manufactured homes overturned or badly damaged, garage doors blown in, trees snapped. EF1 tornadoes cause the majority of mobile home fatalities.

EF2: Significant damage. Roofs torn completely off well-built frame homes, large trees snapped or uprooted, boxcars overturned, vehicles thrown.

EF3: Severe damage. Entire stories of well-constructed homes destroyed, heavy cars lifted and thrown, trees debarked by sand-blasted debris.

EF4: Devastating damage. Well-built homes leveled to their foundations, cars thrown great distances, large steel-framed structures badly damaged.

EF5: Incredible damage. Strong frame homes swept completely away, leaving only the concrete slab. High-rise buildings suffer structural damage. Asphalt stripped from roadways. EF5 tornadoes have touched down in Joplin, Missouri (2011) and Moore, Oklahoma (2013), among other locations — events that define what extreme tornado damage looks like at the neighborhood scale. The scale's methodology is detailed on the event classification methodology page.

The single most important predictor of whether a tornado kills someone is not the tornado's intensity — it is whether that person was in a mobile or manufactured home when the storm struck. Mobile homes account for roughly 40% of all U.S. tornado fatalities despite housing approximately 6% of the population. In a violent tornado, a mobile home offers essentially no more protection than being outdoors.

The engineering reasons are straightforward. Manufactured housing is built to resist wind loads far below tornado-force winds. Without a continuous load path from roof to foundation — and without a below-grade basement to shelter in — the structure fails rapidly and catastrophically. Even tie-down anchoring systems designed to prevent overturning in high winds do not keep the structure intact when tornado winds exceed EF2 intensity. The walls fail first, then the roof separates, then residents are exposed to flying debris and often ejected from the home entirely.

The policy response has two tracks. Community storm shelters, funded partially through FEMA's Hazard Mitigation Grant Program, provide neighborhood-scale below-grade refuges for manufactured housing communities and rural residents without basements. The program has built thousands of shelters since the 1990s. FEMA safe rooms — hardened above-grade rooms that can be installed in existing homes — offer a second option where excavation is impractical.

The most important action for any manufactured home resident is to identify their nearest shelter before tornado season begins, not during a warning when minutes matter. The intersection of poverty, manufactured housing, and tornado risk is not accidental — communities with fewer resources to build or retrofit to storm-resistant standards suffer disproportionate casualties. For a broader view of severe weather threats including hurricanes and tsunami risks, see the companion tracker pages.