APPENDIX: Peak Record Flows on Colorado River By Year (1997-2012)

Appendix B
Peak Flows by Year

Grizzly Creek at 16,000 cfs in 2011

This data shows the date and peak of the Colorado River at the two river gauges for the Colorado River that are relevant to this book. The Dotsero gauge, located just below the confluence of the Eagle (river mile .5) and the “Below Glenwood Springs” gauge, is not far downstream of Two Rivers Park at (mile 20.1.)

Year Date Dotsero       Below Glenwood Spgs
1997 June 4 16,100 cfs
       June 5                                     23,400 cfs
1998 June 2 7,550 cfs
       June 2                                    12,800 cfs
1999 June 9 8,310 cfs
       June 9                                     13,000 cfs
2000 May 30 8,790 cfs
       May 30                                    13,800 cfs
2001 May 20 4,400 cfs
       June 2                                       8,130 cfs
2002 June 1 2,020 cfs
       June 1                                       4,480 cfs
2003 June 2 11,700 cfs
       June 2                                     18,500 cfs
2004 June 8 3,240 cfs
       June 8                                       6,920 cfs
2005 May 24 7,390 cfs
       May 23                                    12,800 cfs
2006 May 23 9,600 cfs
       May 23                                    14,600 cfs
2007 June 19 6,720 cfs
       June 20                                   10,700 cfs
2008 May 22 13,000 cfs
        June 3                                    20,300 cfs
2009 May 21 10,400 cfs
        May 21                                   17,800 cfs
2010 June 8 14,600 cfs
       June 8                                     24,300 cfs
2011 June 7 18,500 cfs
        June 26                                  27, 600 cfs
2012 July 24 5,020 cfs*
       July 25                                      4,480 cfs*

*Due to the extremely low snow pack in the winter of 2011-2012, the peak flow for both gauges in 2012 was due to rainfall, not snowmelt
(source: USGS http://nwis.waterdata.usgs.gov)

FLOW GUIDE Colorado River in Glenwood Canyon

Glenwood Canyon Flow Guide

0 to 2,000 cfs Low

Very common level during the summer, fall and early spring seasons. Grizzly is mellow (II) though shallow in spots, Shoshone is straightforward (III), and Barrel is mostly dry due to the diversion.

2,000 to 5,000 cfs Medium

Banks starting to fill in. Popular and fun level. Grizzly is deeper and pushier but still manageable by a strong beginner. Shoshone is getting juicy and starting to show a little muscle, especially above 4,000 cfs. Long swims and flipped rafts are possible. Barrel is filled in a pushy. This is the level in which most Barrel descents occur. Class V around 3,000 cfs and up.

5,000 to 10,000 cfs High

Now we’re talking! Only the biggest rocks are still exposed. Grizzly has some surprising waves and powerful currents (III), Shoshone is pushy class IV with some ugly, well-spaced monster holes, and Barrel is top-expert V+.

Above 10,000 cfs Very High

Yee-haw! Monster waves and very strange currents throughout. Only experienced paddlers should attempt even the easy sections. Grizzly is pushy and swirly (III), Shoshone is starting to flush but has gigantic moments and brutal consequences (IV), and Barrel is utterly heinous. How high can it get? In 2011 the river peaked just under 19,000 cfs. In both 1983 and 1984, the two highest water years on record, the river peaked over 20,000 cfs.