Water Year 2012: Review of hydrologic Conditions that

impacted forecasts in the Colorado River Basin

CRFS November 14, 2012

Water Year 2012:Entering the Season (what did we know in the fall):

Coming off major runoff year - Soil Moisture (not bad) - Baseflow (not bad)La Nina Conditions (no help)

The Winter:Reasonable, up until March

The Spring:Disastrous…

CBRFC Model Soil Moisture11/1/11

USGS Monthly Average StreamflowOctober 2011(includes regulated flows)

Were Entering 2nd year of La Nina conditions

Sources: cpc.ncep.noaa.gov and iri.columbia.edu/climate/ENSO

CPC Precipitation Outlooks Nov 17,2011

CPC Climate Forecast December 15, 2011

CPC Climate Forecast February 16, 2012

In March things begin to go horribly wrong

April, May, and June were extremely dry. Over many basins, these three months combined were among the driest AMJs on record.

April 2012 Precip anomalies

May 2012 Precip anomalies June 2012 Precip anomalies

March 2012 Precip anomalies

The DRY !!

Source: www.prism.oregonstate.edu

The Heat !!

Snowpack Decimation – well under way

Snowpack essentially gone except for the Wind River Range

USGS Monthly Average Streamflow(includes regulated flows)

March 2012 May 2012