This market will resolve according to the lowest gage height (river level), in feet, recorded at the Mississippi River at St. Louis, MO streamgage (USGS site 07010000) between market creation and November 30, 2026, as published by the United States Geological Survey (USGS) for parameter code 00065 under statistic code 30800. Exactly one outcome in this market will resolve to "Yes". The lowest daily reading in the window decides this market; the level does not need to be sustained. If USGS does not publish a reading for one or more days, this market will resolve according to the lowest reading among the days that are published. Values will be used exactly as published by USGS, without rounding. USGS reports gage height at this gage to 2 decimal places. Each range includes both of its stated bounds and consecutive ranges are contiguous, so every reading falls in exactly one range: a lowest reading of exactly -1.00 ft resolves the range beginning at -1.00 ft to "Yes" and every other range to "No". This market will resolve on the values published at the time of resolution, whether flagged provisional ("P") or approved ("A"); revisions published afterward will not be considered, except where the correction provision below applies. If any data remains unpublished or unfinalized, this market will remain open for up to 2 calendar days (ET) after November 30, 2026; it will then resolve based on the finalized data published up to that point. In case of obvious data integrity issues (i.e., erroneous data), the market may remain open until the end of the third calendar day (ET) after such data is first released to allow for corrections; this applies only to clerical or similar errors, not to USGS differing from other sources. If the source is unavailable, this market may be extended to December 15, 2026, 11:59 PM ET. If no data for the window is available by then, this market will resolve to "Below -3.00 ft". The primary resolution source for this market will be the USGS Daily Values service for site 07010000; however, a consensus of credible reporting may also be used. The service is available here: https://waterservices.usgs.gov/nwis/dv/?sites=07010000&parameterCd=00065&statCd=30800&startDT=2026-09-21&endDT=2026-11-30&format=rdb