In other words, in the coming months, Lake Powell will see new record low elevations every month until the west exits its drought. The final number is the current “most probable” projection for the lake level at the end of 2021.Seeing April of this year as next on the list bucks that trend and shows the significance of the drought. We’d expect those to be the lowest months as the lake replenishes in spring with levels ebbing until the next spring. The previous lowest monthly averages were January-March of 2005.WATCH: Earth Engine from Google shows Utah changing over time These are the four months of the lowest average lake levels on record since 1970, after the reservoir was initially filled. Seeing those inflows, this last chart should be no surprise. WATCH: Shrinking shoreline exposes shipwreck at Lake PowellĪfter looking through those, and the inflows in the 60s as well, we compared Spring 2021 thus far to the 11 other worst years for spring runoff: Each decade’s chart has a different scale to match the highest average cfs within the time frame, so the 1980s chart extends above 80,000 cfs.Each decade has seen down years, though this year is extraordinary. In this case, it’s averaged out over each month. It’s the standard measure for stream flows tracked for over a century, but simply indicates the amount of water that flows either by a point or into a point at one moment in time. These charts show cubic feet per second (cfs) flowing in.
READ: Cox issues another executive order to combat ongoing drought The question we asked: Is the current downturn normal for the Lake’s cycle? To answer, we examined every spring since 1963 and charted all since 1970. The shaded areas show how spring runoff has replenished the water supply each year, except 2021 where forecasts from the Bureau of Reclamation now estimate inflow from the Colorado, San Juan and smaller tributaries will not exceed outflow.