Riverside Reservoir, CO – Tornado 21 July 2000

Date: 21 July 2000


Location: Lone Bridge Road Exit off of I-76 West of Fort

Morgan, CO


Time Frame: Approx 1800-1820 MDT


Chase Summary:


I sat near Anton, CO for about 1:30.   I could see that storms were firing up near the CO/WY border and decided to head north at about 1500 MDT.   North of Brush, CO I sat and waited for about another hour.   I

watched a slow moving LP Meso during that time pass near me, but nothing developed.   Meanwhile, to my S and SE I was watching some pretty violently shooting towers going up.  I decided to trek back toward Brush.  I was just starting to head E on Hwy 34 when the siren on my scanner went off.   All I heard was “Tornado Warning”, but for where I could not tell, because it had cut out.   So I called my Now Caster (My mom in Michigan) and had her check out where.  The Warning was for Weld and Morgan Counties.   Looking NW you could see forever and I was in disbelief because it seemed as though nothing was happening there to me, with the exception of one low hanging cloud.   So I sat and observed it for about 5 minutes and it was definitely taking a Wall Cloud appearance.  I then proceeded to get on I-76 and headed West.   Since the storm was moving somewhat  in my direction I decided to exit the Interstate and just set up shop where I was.  I had good escape routes covering East and West.  So I basically put my small tripod on the roof of my car, hit “record”, stood back and just watched.  After about 2 minutes there was circulation on the ground.  I immediately called it in to NWS.  From the time the Tornado Warning was issued til the first touch down was roughly 25 minutes, during which you could see the entire event unfold from nearly 35 miles away or even further when I first saw what had developed into the Wall Cloud.  After a few minutes a second funnel developed on the outer side of the Wall Cloud and touched down briefly.  For a first tornado, I don’t think I could have fashioned one together that would be as impressive.   To my knowledge, the only damage this tornado caused was to some trees.  It was very graceful and slow moving and had dissipated before crossing I-76 and going into Wiggins, CO.

Well formed wall cloud and mesocyclone


Note the small funnel coming out of the left side of the mesocyclone.   It did touch down briefly.

Riverside Reservoir Tornado at it’s peak.

Roping out.

Mammatus clouds north of Last Chance on Highway 71

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