Weather alerts in Louisiana, 2010
2,156 weather alerts in 2010, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2010. Tap one for its archive.
- Alerts
- 2,156
- Warnings
- 1,315
- Watches
- 114
- Advisories
- 549
- Busiest month
- June306 alerts
- Busiest day
- April 24, 201050 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
20 of 84 tornado warnings covering Louisiana in 2010 had a tornado report inside them; 31 of 46 tornado reports fell inside a warning, on average 16 minutes after it went out.
Louisiana, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 84 | 20 | 76% | 46 | 67% | 16 min |
| Severe thunderstorm warnings | 370 | 147 | 60% | 310 | 69% | 20 min |
| Flash flood warnings | 51 | 24 | 53% | 42 | 71% | 87 min |
Each office's whole area, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Jackson, MS: tornado warnings | 111 | 29 | 74% | 97 | 89% | 32 min |
| NWS Jackson, MS: severe thunderstorm warnings | 620 | 337 | 46% | 707 | 75% | 20 min |
| NWS Jackson, MS: flash flood warnings | 111 | 54 | 51% | 102 | 91% | 60 min |
| NWS Shreveport, LA: tornado warnings | 77 | 20 | 74% | 46 | 85% | 19 min |
| NWS Shreveport, LA: severe thunderstorm warnings | 288 | 152 | 47% | 358 | 77% | 21 min |
| NWS Shreveport, LA: flash flood warnings | 14 | 11 | 21% | 39 | 79% | 166 min |
| NWS New Orleans, LA: tornado warnings | 49 | 6 | 88% | 10 | 60% | 17 min |
| NWS New Orleans, LA: severe thunderstorm warnings | 154 | 30 | 81% | 67 | 55% | 19 min |
| NWS New Orleans, LA: flash flood warnings | 27 | 8 | 70% | 12 | 75% | 73 min |
| NWS Lake Charles, LA: tornado warnings | 18 | 6 | 67% | 28 | 57% | 15 min |
| NWS Lake Charles, LA: severe thunderstorm warnings | 63 | 29 | 54% | 91 | 62% | 22 min |
| NWS Lake Charles, LA: flash flood warnings | 15 | 7 | 53% | 18 | 83% | 89 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
2,156 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- East Carroll Parish161
- Saint Bernard Parish154
- Tensas Parish153
- Madison Parish152
- Saint John the Baptist Parish142
- Bossier Parish142
- Washington Parish140
- Morehouse Parish137
- East Baton Rouge Parish134
- Saint Martin Parish134
- Franklin Parish134
- West Carroll Parish131
- Caddo Parish131
- West Feliciana Parish127
- Webster Parish127
- East Feliciana Parish125
- Pointe Coupee Parish125
- Richland Parish124
- Claiborne Parish124
- Assumption Parish123
- Concordia Parish123
- Saint James Parish122
- Saint Helena Parish121
- Union Parish121
- Rapides Parish120
- Ouachita Parish120
- Lafayette Parish118
- Saint Landry Parish117
- West Baton Rouge Parish116
- Avoyelles Parish115
- Jackson Parish114
- Winn Parish114
- Lincoln Parish113
- De Soto Parish112
- Iberville Parish110
- Bienville Parish110
- Natchitoches Parish110
- Catahoula Parish108
- Evangeline Parish103
- Caldwell Parish101
24 more counties
- Beauregard Parish100
- Vernon Parish99
- Red River Parish99
- Allen Parish97
- Sabine Parish97
- LaSalle Parish92
- Grant Parish90
- Saint Tammany Parish84
- Tangipahoa Parish64
- Jefferson Parish64
- Lafourche Parish58
- Calcasieu Parish56
- Livingston Parish56
- Orleans Parish52
- Saint Charles Parish52
- Plaquemines Parish46
- Ascension Parish43
- Acadia Parish40
- St. Mary Parish35
- Vermilion Parish35
- Jefferson Davis Parish33
- Terrebonne Parish32
- Iberia Parish31
- Cameron Parish22
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20092011
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.