A strong spring storm system moved from the central Plains into the Great Lakes region from 12 March to 13 March 2006.  An initial low level jet of 30-40 knots increased to 40-50 knots after sunset on 12 March which increased the available moisture for thunderstorms and heavy rain development.A series of upper level disturbances developed waves of thunderstorms during the afternoon and overnight hours along and north of the warm front.  Low freezing and wet bulb zero levels north of the warm front resulted in the storms being prolific hail producers.  Outflow boundaries left over from the initial thunderstorm waves combined with the northward moving warm front provided the focus for locally heavy rainfall that lead to flash flooding in the Quad Cities metropolitan area.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 12-MAR-06 21:30:00 to 12-MAR-06 21:30:00 (CST)
Location: MORRISON
Magnitude: 57 EG
Property damage: 25K
Reported by: LAW ENFORCEMENT

15 power poles snapped at ground level on Frog Pond Road between Garden Plain and Hazel Roads.

Hail in CARROLL, ILLINOIS
From 12-MAR-06 21:30:00 to 12-MAR-06 21:30:00 (CST)
Location: THOMSON
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Heavy Rain in WHITESIDE, ILLINOIS
From 12-MAR-06 22:04:00 to 12-MAR-06 22:20:00 (CST)
Location: PROPHETSTOWN
Reported by: TRAINED SPOTTER

minor flooding of lower streets

Thunderstorm Wind in MCDONOUGH, ILLINOIS
From 13-MAR-06 00:15:00 to 13-MAR-06 00:15:00 (CST)
Location: ADAIR
Magnitude: 52 EG
Property damage: 1K
Reported by: TRAINED SPOTTER

Power poles were downed near Adair.

Hail in ROCK ISLAND, ILLINOIS
From 12-MAR-06 20:06:00 to 12-MAR-06 20:06:00 (CST)
Location: ILLINOIS CITY
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

marble to dime size hail

Hail in HENRY, ILLINOIS
From 12-MAR-06 21:25:00 to 12-MAR-06 21:25:00 (CST)
Location: GALVA
Magnitude: 0.75 
Reported by: GENERAL PUBLIC

Delayed report.  Time estimated based on radar.

Thunderstorm Wind in WARREN, ILLINOIS
From 12-MAR-06 22:17:00 to 12-MAR-06 22:20:00 (CST)
Location: KIRKWOOD
Magnitude: 52 EG
Property damage: 2K
Reported by: TRAINED SPOTTER

limbs down

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 12-MAR-06 22:12:00 to 12-MAR-06 22:19:00 (CST)
Location: GERMAN VLY
Magnitude: 70 EG
Property damage: 2K
Reported by: NEWSPAPER

The bow echo that developed and raced across Whiteside and Carroll counties caught the far southeast corner of Stephenson County.  The apex of the bow passed right over German Valley and snapped off trees a few feet above the base.

Hail in HENDERSON, ILLINOIS
From 12-MAR-06 14:33:00 to 12-MAR-06 14:36:00 (CST)
Location: MEDIA
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

dime size hail

Hail in CARROLL, ILLINOIS
From 12-MAR-06 21:55:00 to 12-MAR-06 21:55:00 (CST)
Location: MT CARROLL
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

dime size hail

Hail in WARREN, ILLINOIS
From 12-MAR-06 22:15:00 to 12-MAR-06 22:15:00 (CST)
Location: LITTLE YORK
Magnitude: 1.00 
Property damage: 5K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in MERCER, ILLINOIS
From 12-MAR-06 22:18:00 to 12-MAR-06 22:18:00 (CST)
Location: MATHERVILLE
Magnitude: 52 EG
Property damage: 6K
Reported by: TRAINED SPOTTER

power poles and branches down

Thunderstorm Wind in HENRY, ILLINOIS
From 12-MAR-06 22:50:00 to 12-MAR-06 22:50:00 (CST)
Location: ATKINSON
Magnitude: 83 EG
Property damage: 300K
Reported by: TRAINED SPOTTER

A bow echo interacted with a surface boundary over Atkinson and produced a ducted downburst over a narrow path of about 1 mile.  About 12 homes sustained varying amounts of damage with many trees either uprooted or damaged.  An RV wasflipped onto its side.At the Atkinson Grain & Fertilizer plant a 100 foot leg was torn away and dropped on the railroad tracks where it was hit by a slow moving train several hours later.

Thunderstorm Wind in WARREN, ILLINOIS
From 12-MAR-06 22:15:00 to 12-MAR-06 22:20:00 (CST)
Location: MONMOUTH
Magnitude: 50 EG
Property damage: 2K
Reported by: LAW ENFORCEMENT

Winds estimated at greater than 50 mph from Lake Warren to Alexis.

Hail in HENRY, ILLINOIS
From 12-MAR-06 16:14:00 to 12-MAR-06 16:15:00 (CST)
Location: ATKINSON
Magnitude: 1.00 
Property damage: 2K
Reported by: GENERAL PUBLIC

Based on pictures from WQAD-TV web site.

Hail in WARREN, ILLINOIS
From 12-MAR-06 22:24:00 to 12-MAR-06 22:24:00 (CST)
Location: GERLAW
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Also, heavy rain and estimated 40-50 mph winds.

Hail in MERCER, ILLINOIS
From 12-MAR-06 21:17:00 to 12-MAR-06 21:17:00 (CST)
Location: SHERRARD
Magnitude: 1.00 
Property damage: 5K
Reported by: AMATEUR RADIO

Hail in WHITESIDE, ILLINOIS
From 12-MAR-06 20:48:00 to 12-MAR-06 20:48:00 (CST)
Location: COLETA
Magnitude: 1.00 
Property damage: 3K
Reported by: EMERGENCY MANAGER

Hail in HENDERSON, ILLINOIS
From 12-MAR-06 21:19:00 to 12-MAR-06 21:19:00 (CST)
Location: BALD BLUFF
Magnitude: 0.88 
Reported by: LAW ENFORCEMENT

Heavy Rain in HENRY, ILLINOIS
From 12-MAR-06 19:54:00 to 12-MAR-06 19:54:00 (CST)
Location: COLONA
Reported by: TRAINED SPOTTER

1 to 2 feet of standing water in a mobile home park.  According to the spotter, this area is well known for having poor drainage during heavy rainfall.  Time estimated based on radar.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:54:00 to 12-MAR-06 19:58:00 (CST)
Location: CARBON CLIFF
Magnitude: 57 EG
Property damage: 1K
Reported by: TRAINED SPOTTER

flag pole down

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 12-MAR-06 20:20:00 to 12-MAR-06 20:22:00 (CST)
Location: ERIE
Magnitude: 52 EG
Property damage: 1K
Reported by: EMERGENCY MANAGER

wires down

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:49:00 to 12-MAR-06 19:50:00 (CST)
Location: MOLINE QUAD CITY ARP
Magnitude: 70 EG
Property damage: 10K
Reported by: TRAINED SPOTTER

Limb from a tree went through the window of the Quality Inn.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:53:00 to 12-MAR-06 19:58:00 (CST)
Location: SILVIS
Magnitude: 70 EG
Property damage: 50K
Reported by: TRAINED SPOTTER

A screen door was blown off with damage to a carport.  Severe damage occurred to a car wash.

Thunderstorm Wind in HENRY, ILLINOIS
From 12-MAR-06 19:54:00 to 12-MAR-06 19:57:00 (CST)
Location: COLONA
Magnitude: 57 EG
Property damage: 5K
Reported by: TRAINED SPOTTER

Numerous trees down at the confluence of the Green and Rock Rivers near the Hennepin Canal. Some of the trees were observed to be unhealthy.  Time estimated based on radar.

Hail in CARROLL, ILLINOIS
From 12-MAR-06 20:58:00 to 12-MAR-06 20:58:00 (CST)
Location: MILLEDGEVILLE
Magnitude: 1.00 
Property damage: 3K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:48:00 to 12-MAR-06 19:49:00 (CST)
Location: (MLI) QUAD CITY ARPT
Magnitude: 93 MG
Property damage: 300K
Reported by: AWOS,ASOS,MESONET,ETC

Measured gust from KMLI ASOS that was confirmed by FAA backup equipment. A Hampton Inn under construction on the northeast side of the airport was demolished and a nearby interstate highway sign was blown over.NWS survey concluded a microburst occurred on the west edge of the airport.  Considerable damage was done to a group of homes, outbuildings, power lines, and trees just outside the airport perimeter.  The wind gust of 107 mph bested the old record wind gust of 81 mph at KMLI which was set on 21 August 1987.

Hail in WHITESIDE, ILLINOIS
From 12-MAR-06 20:20:00 to 12-MAR-06 20:26:00 (CST)
Location: MORRISON
Magnitude: 1.00 
Property damage: 3K
Reported by: TRAINED SPOTTER

Hail in PUTNAM, ILLINOIS
From 12-MAR-06 16:15:00 to 12-MAR-06 16:25:00 (CST)
Location: MAGNOLIA
Magnitude: 1.00 
Property damage: 5K
Reported by: TRAINED SPOTTER

multiple reports

Hail in PUTNAM, ILLINOIS
From 12-MAR-06 16:06:00 to 12-MAR-06 16:25:00 (CST)
Location: COUNTYWIDE
Magnitude: 1.50 
Property damage: 20K
Reported by: TRAINED SPOTTER

An intense thunderstorm moved across the southern part of Putnam County producing hail of 1.00 to 1.50 inches. Hail was reported between Magnolia and Mc Nabb in the 1615-1625 CST time period by several spotters.  Additional spotters reported large hail on Illinois 18 west of Magnolia.

Hail in PUTNAM, ILLINOIS
From 12-MAR-06 16:15:00 to 12-MAR-06 16:30:00 (CST)
Location: GRANVILLE
Magnitude: 0.88 
Reported by: EMERGENCY MANAGER

Hail in MERCER, ILLINOIS
From 12-MAR-06 19:00:00 to 12-MAR-06 19:00:00 (CST)
Location: JOY
Magnitude: 1.00 
Reported by: LAW ENFORCEMENT

nickel to quarter sized hail

Hail in MERCER, ILLINOIS
From 12-MAR-06 19:00:00 to 12-MAR-06 19:00:00 (CST)
Location: MANNON
Magnitude: 1.00 
Property damage: 5K
Reported by: LAW ENFORCEMENT

Nickel to quarter sized hail.

Thunderstorm Wind in MERCER, ILLINOIS
From 12-MAR-06 19:25:00 to 12-MAR-06 19:25:00 (CST)
Location: MATHERVILLE
Magnitude: 52 EG
Property damage: 5K
Reported by: TRAINED SPOTTER

Trees and power lines down

Thunderstorm Wind in HENRY, ILLINOIS
From 12-MAR-06 19:50:00 to 12-MAR-06 19:50:00 (CST)
Location: ORION
Magnitude: 61 EG
Reported by: TRAINED SPOTTER

Estimated 70 mph

Thunderstorm Wind in MERCER, ILLINOIS
From 12-MAR-06 19:18:00 to 12-MAR-06 19:22:00 (CST)
Location: ALEDO
Magnitude: 52 EG
Property damage: 5K
Reported by: OFFICIAL NWS OBS.

Trees and power lines down

Hail in PUTNAM, ILLINOIS
From 12-MAR-06 16:06:00 to 12-MAR-06 16:06:00 (CST)
Location: PUTNAM
Magnitude: 0.75 
Reported by: GENERAL PUBLIC

2 minute duration just north of the Putnam/Marshall county line.

Thunderstorm Wind in BUREAU, ILLINOIS
From 12-MAR-06 23:05:00 to 12-MAR-06 23:09:00 (CST)
Location: WALNUT
Magnitude: 57 EG
Property damage: 3K
Reported by: OFFICIAL NWS OBS.

branches a couple of inches in diameter down across the town

Thunderstorm Wind in HENRY, ILLINOIS
From 12-MAR-06 22:52:00 to 12-MAR-06 22:52:00 (CST)
Location: ATKINSON
Magnitude: 78 EG
Property damage: 12K
Reported by: TRAINED SPOTTER

A bow echo moved across Henry County at around 52 knots (60 mph) and produced a downburst that destroyed a farm outbuilding (that doubled as a garage) and scattered it across a nearby field.  Time estimated based on radar.

Thunderstorm Wind in BUREAU, ILLINOIS
From 12-MAR-06 23:08:00 to 12-MAR-06 23:12:00 (CST)
Location: WALNUT
Magnitude: 61 EG
Property damage: 1K
Reported by: TRAINED SPOTTER

A door was blown off a barn.  Time estimated based on radar.

Thunderstorm Wind in BUREAU, ILLINOIS
From 12-MAR-06 23:20:00 to 12-MAR-06 23:20:00 (CST)
Location: PRINCETON
Magnitude: 57 EG
Property damage: 2K
Reported by: TRAINED SPOTTER

power pole down on Backbone Rd

Thunderstorm Wind in MERCER, ILLINOIS
From 12-MAR-06 22:20:00 to 12-MAR-06 22:20:00 (CST)
Location: NORTH HENDERSON
Magnitude: 52 EG
Property damage: 6K
Reported by: TRAINED SPOTTER

power poles and branches down

Hail in PUTNAM, ILLINOIS
From 12-MAR-06 23:50:00 to 12-MAR-06 23:50:00 (CST)
Location: MC NABB
Magnitude: 0.88 
Reported by: LAW ENFORCEMENT

Flash Flood in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:53:00 to 13-MAR-06 01:00:00 (CST)
Location: MOLINE
Property damage: 50K
Reported by: TRAINED SPOTTER

Thunderstorms trained across the Quad City Metro area and produced rainfall rates exceeding 1 inch per 30 minutes.  Spotters, amateur radio, and the media reported numerous roads flooded out or cars floating. By 2015 CST KWQC-TV was reporting cars floating in parts of Rock Island.  AT 2030 CST two reports indicated 11th Street and 14th Avenue in Rock Island was under water with 11th Street flooded in other spots.KMLI ASOS reported 1.78 inches of rain for 12 March 2006 of which 1.66 inches fell during the 1800-2400 CST time period. At the same time, the KDVN ASOS reported 1.05 inches of rain for 12 March 2006. The heaviest rain occurred during the 1900-2300 CST time period in a narrow band in between the two ASOS sites.  The highest know rainfall amount occurred in central Davenport where 3.50 inches of rain fell. The closeness of the heavy rainband to the KDVN 88D resulted in a severe underestimation of the rainfall. Rainfall estimates from the distant KILX and KLOT 88D sites indicate 3-4 inches of rain fell.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 12-MAR-06 19:48:00 to 12-MAR-06 19:48:00 (CST)
Location: MOLINE
Magnitude: 57 EG
Property damage: 10K
Reported by: TRAINED SPOTTER

Many trees were downed across the city.  Trinity Medical Center on 7th Street lost all electrical power for several hours. Limited power was available for the facility through emergency generators.

Hail in HENRY, ILLINOIS
From 12-MAR-06 22:59:00 to 12-MAR-06 22:59:00 (CST)
Location: ANNAWAN
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Also heavy rain; truck struck by lightning