Three EF-1 Chicago Tornadoes have been confirmed in the southern suburbs of Chicago after a round of severe weather swept through the area, bringing damaging winds, heavy rain and dangerous conditions. Before confirming the tornado sightings, storm survey teams checked out damaged buildings, trees, power lines and other evidence left behind by the storms. Residents throughout the Chicago area continue clean-up efforts, but meteorologists continue to analyse the larger severe-weather event.
Three Tornadoes Confirmed, One EF-1 Reported
The National Weather Service surveys storm damage to determine if a tornado occurred and how strong it was.
That would be an EF-1 on the Enhanced Fujita Scale with estimated winds of 86 to 110 miles per hour. Those big tornadoes can rip roofs off buildings, flip over mobile homes, break big tree limbs and toss cars off roads.
EF-1 tornadoes are not the strongest, but they can be dangerous and costly.
South suburbs of Chicago get a hard hit
The tornadoes that tore through northeastern Illinois brought their force to communities in the southern suburbs of Chicago, swept across the area by torrential thunderstorms.
Conditions may have been changing quickly, with damaging winds and heavy rain arriving in a short period of time for residents.
Tornado paths are narrow, and damage from a storm can be quite different from one neighbourhood to another. One house can be badly damaged and a neighbouring house can be comparatively undamaged.
Teams of storm surveyors mapped out damage paths
“Tornadoes are often confirmed by the pattern of damage, not just radar,” said meteorologists.
The debris is typically blown in the same direction in straight line thunderstorm winds. Signs of rotation or convergence may be seen in tornado damage.
Survey teams also look at structural damage, downed trees, radar data, eyewitness accounts and pictures to assign an EF rating.
Final ratings and path information are subject to change as more evidence is evaluated.
Tornado Damage May Cause Power Outages
Severe thunderstorms and tornadoes frequently cause damage to the electrical infrastructure.
Utility poles or transformers may be damaged by lightning strikes or trees fall on distribution lines and cause power outages. Those problems can leave thousands of customers in the dark long after the storms have ended.
Restoration may take longer in neighbourhoods where utility crews need to first clear trees or make damaged areas safe.
Cleanup Poses Additional Safety Hazards
But those returning to storm-damaged homes still need to be cautious.
Assume the down lines are energised. Other hazards can include broken glass, exposed nails, unstable walls and damaged trees.
Avoid entering buildings that are badly damaged until local authorities or qualified professionals have determined that they are safe structurally.
Poorer weather may hamper recovery
Additional rain or thunderstorms can slow the cleanup and restoration process following a major storm event.
Weakened trees can fall in the next wind gusts and damaged roofs allow more water into homes and businesses.
The threat from the first tornado has passed, but residents should continue to monitor the National Weather Service forecast.
Sources
- National Weather Service – Official tornado confirmations, damage surveys, severe weather warnings, storm reports
- NOAA – Enhanced Fujita Scale Tornado Science and Severe Weather Information
- Fox 32 Chicago – Local Reports of 3 EF-1 Tornadoes in South Suburbs of Chicago
- Ready.gov – Federal Tornado Safety Information & Emergency Preparedness
