Mississippi River at Mel Price (Alton) Lock and Dam

1. 42.70 ftThis is the RECORD FLOOD LEVEL that was reached on August 1 1993.
2. 42.00 ftNear this height U.S. Highway 67 will be completely closed. (MoDOT)
3. 40.00 ftRailroad tracks from Wood River to Alton begin to flood.
4. 37.60 ftDamage begins to Ardent Mills grain bins in Alton within a foot of this height.
5. 36.10 ftThis represents the height of the Lincoln Shields levee just below the Missouri side of the Clark bridge.
6. 35.50 ftAt this approximate stage, Mel Price Lock and Dam must close the lock to navigation. This happened on July 10, 1993.
7. 34.50 ftNear this height, the southbound lanes of U.S. Highway 67 will begin flooding, forcing the detour of southbound traffic onto the northbound lanes.
8. 34.20 ftNear this height water will begin flowing over Riverlands Way between Highway 67 and Mel Price Locks and Dam. This road is a part of the Consolidated North County levee, so this is the point when water begins gradually flowing onto the protected farmland and farm homes behind the levee.
9. 32.90 ftRiverfront Park in Alton begins flooding.
10. 31.50 ftCommercial basements in Alton begin to flood within a foot of this height.
11. 30.50 ftBloch Marine Service at the Harbor Point Yacht Club begins flooding within a foot of this level.
12. 29.90 ftRoute 100 at Alton closes within a foot of this height. Also at this level the north and south Wood River Levee structures are closed.
13. 29.30 ftThe North Wood River Levee must be closed at this level.
14. 28.80 ftHighway 100 will begin flooding at Clifton Terrace Street within 2 feet of this height.
15. 28.50 ftThe South Wood River Levee must be closed at this level.
16. 27.90 ftMissouri Highway 94 from Alta Villa Road to Feltes Drive will be closed near this height.
17. 26.60 ftWithin a foot of this height, outer road US 67 between Riverlands Way and the Lincoln Shields Access Road will close due to flooding.
18. 26.50 ftYachtview Drive begins flooding along the entrance to Harbor Point Yacht Club within a foot of this height.
19. 25.00 ftHighway 94 and the east end of Harbor Point Road off of Highway 94 north of West Alton begin flooding within a foot or so of this height. Also, the access road to the Lincoln Shields area off Highway 67 just west of the Clark bridge begins flooding.
20. 24.00 ftAlta Villa Road off of Highway 94 north of West Alton is closed within a foot of this height.
21. 23.00 ftDresser Island Drive floods within a foot of this level.
22. 20.80 ftUnprotected farm land begins to flood
23. 18.00 ftNear this height, Mel Price Lock and Dam will go to "open river" conditions, lifting all gates out of the river.

Chance of flooding, September to November

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 28, 2026.

Most recent crests

• May 1, 2026: 24.30 ft
• May 2, 2024: 23.62 ft
• June 28, 2021: 23.17 ft
• April 14, 2021: 22.90 ft
• March 20, 2021: 25.04 ft
• June 1, 2020: 25.14 ft
• May 19, 2020: 22.16 ft
• April 30, 2020: 22.32 ft
• March 25, 2020: 23.72 ft
• January 13, 2020: 23.33 ft

• UpstreamMississippi River at Alton
• DownstreamMississippi River at St. Louis
• Mississippi River at Grafton
• Missouri River at St. Charles
• Dardenne Creek at St. Peters
• Meramec River at Valley Park
• Meramec River at Fenton
• Silver Creek

Forecasts by the North Central River Forecast Center. Forecasts are issued routinely year-round. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 24 hours into the future from the forecast issuance time. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 48 hours into the future from the forecast issuance time. For the latest navigation status update from the U.S. Army Corps of Engineers-St. Louis District, <a href="http://www.mvs.usace.army.mil/Missions/Navigation/Status-Reports/">click here.</a>

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.