”Bow Echo” sweeps across Washtenaw County on May 21, 2004
| Time | Action/Event |
| 1103 | Flash Flood Watch issued by the National Weather Service until 0600 Saturday. Emergency Management Division staff initiated emergency fan-out. |
| 1155 | Severe Thunderstorm Watch issued by the National Weather Service. Initiated emergency fan-out and staff was notified to activate Emergency Communications Center. |
| 1336 |
Severe Thunderstorm Warning issued by the National Weather Service until 1430. Initiated emergency fan-out and activated Skywarn Spotter network. Doppler radar indicated a line of intense thunderstorms in Jackson County moving east at 55 MPH. |
| 1348 | Skywarn Spotters reported 1" hail on the west side of Ann Arbor. |
| 1402 | Skywarn Spotter reported 1" hail, 60 MPH winds and 8" tree downed in Freedom Twp. |
| 1415 | Flash Flood Warning issued by the National Weather Service until 1615. All area departments and Skywarn Spotters were advised to expect flooding rainfall. |
| 1420 | Skywarn Spotters reported 2" hail falling in Ypsilanti Twp., and a 7" tree downed onto power lines in Salem Township. |
| 1420 | Numerous reports of power outages were received in the vicinity of Chelsea, Dexter, Pittsfield Township and Ypsilanti Township. Numerous additional outages were reported from across Washtenaw County. |
| 1429 | Severe Thunderstorm Warning cancelled by the National Weather Service. Numerous reports of flooded streets (some covered with up to four feet of water), fallen trees (up to 12" in diameter) and downed power lines were received from across the county. Several of the roads were impassable due to tree debris. |
| 1520 | Public Safety personnel reported ten electrical/telephone poles were blown down by wind along Wagner Road south of Scio Church Road in Lodi Twp. |
| 1600 | Skywarn Spotter reported a 12" diameter tree was blown down across North Territorial Road near Spencer Road in Northfield Twp. |
| 1700 | Emergency Management staff contacted local agencies and confirmed no critical infrastructure failures. DTE reported approx. 27,000 customers without electrical power. |
