Yesterday I had a message from our CoCoRaHS coordinator, Nolan Doesken, in Colorado. I thought some of you who know Colorado might be interested in the weather out there this week. The storm Nolan wrote about in his "newsletter" to volunteer precipitation recorders happened on Monday, I believe. He had written an e-mail the night before warning us, "When it roars (thunder), go in doors."

2:52 a.m. 6/23/2009
It was a dark and stormy night - - -

Just hit delete if you don't have time to read.  But this evening's
weather here was incredible.  I took a short bike ride after sending the
earlier message.  Most of the sky was clear as it had been all day  --
really clear.  It was the clearest day in many weeks, in fact.
Temperatures were in the 70s and the air had a nice moist feel to it and
spring fragrance on the light easterly breeze.  There was one cloud just
east of town and another to the SW -- very high-based cumulus clouds  --
beautiful but not threatening.   Instead of dissipating as clouds here
often do at sunset, these kept billowing.  Before I got home, a few big
raindrops splatted on the pavement.  Strange, I thought  -- those were
really big rain drops.  I went out to bring in the horses and the first
bolt of lightning stuck -- only a mile away.  I thought briefly about
how awful it would be to be struck by lightning, especially just an hour
after sending out the message 'When thunder roars, go indoors"  How ironic.

Within another 20 minutes it was lightning frequently  -- no rain --
just lightning.  Then came the squall of rain followed by hail pushed by
strong winds from the NW.  Within a few minutes, we lost sight of our
neighbors house through the spray.  The hail on the roof was deafening. 
The yard was covered by hail (again!) and the garden that had survived
the previous storms was flat (again).  Lightning flashed every second
for close to 90 minutes.  When it was all done, nearly 2" of rain had
fallen here.  It was probably even more.  I didn't have time to take the
funnel off my gauge, so most of the hail stones bounced out.   Reports
of over 3.00" of rain with 4" of hail on the level have trickled in this
evening from areas a few miles west and north of here..  We'll be
anxious to see the reports and maps tomorrow.  And all of this was on a
day with a forecast of sunny skies with just a 10% chance of late day
storms.  We certainly got our money's worth from that  10%.


Hail on the level

I have a question for you.  Have you ever been in a storm that dropped
huge quantities of hail?  I'm talking about the kind of storm that
covered the ground and left it ice covered for a day or more.  These are
the kind of events where dense fog may form and linger immediately over
the hail-covered ground.   We know that thunderstorms will sometimes
deposit a few inches of hail -- enough to make the ground totally white
-- maybe as much as 4" on the level.  How much hail can a storm
deposit?  Is there an upper limit or could it be a foot  -- or two feet?

Without counting the piles of hail that are deposited by flowing water
or which accumulate at the edge or corner of a building or by the
downspout, I would like to know the deepest accumulation of hail ON THE
LEVEL that you have ever seen?  If you have seen over 6" on the level
and have photos to prove it, we'd like to see it.  We'd like to know. 
We've heard people tell stories of a foot of hail.but we have no proof.

If you encounter one of those prolific hail producers, measure it,
document it and then let us know.  Don't let roofs and gutters cause you
to exaggerate.  Only measure where the hail fell directly and
accumulated uniformly.  If you take photos, make sure you put something
of a known length in the picture-- like a ruler or even a shoe or a
hand.  Also take photos of the fog banks that form when warm moist winds
blow over deep piles of hail.  And for bonus points, measure the water
content of that ice.  There are several occasions of roofs collapsing
under the weight of hail.  But how much did it weight?  That requires
measurements are wise estimates.   Engineers have to figure out how to
design for things like this.


Quiet now

The storm has passed.  Some distant lightning still flickers, but the
sky is now dotted with stars.   My June rainfall total stands at 5.76" 
-- that's a lot for here.
There will be more muddy paws tomorrow, and a sloppy horse corral
again. The grass will stay green until the 4th of July.  And as for the
garden  -- we'll assess damages in the morning.

Good night.

Nolan

Note: I have recorded 2.24" of rainfall for the month of June here at my rain station.