Colorado State University State Climatologist’s Office to Keep Official Hailstone Records for Colorado


Here’s the release from Colorado State University (Emily Narvaes Wilmsen):

As large as a grapefruit? A DVD? A softball? Just how big is the record-holding hailstone in Colorado? Colorado State University State Climatologist Nolan Doesken can list at least 18 separate reports of hail stones as large as 4.5 inches in diameter, but few have been officially confirmed.

His office is now officially tracking these statistics – just in time for spring storms like the one that hit Colorado’s eastern Plains earlier this month, leaving piles of hail on roads and farms.

“Chances are there are at least 50 people in eastern Colorado who will say, ‘What the heck, we’ve seen way bigger hail than that!’” Doesken said. “That’s good, but they will need to prove their claim – by providing the stone itself or eyewitness reports along with excellent photos showing the stone with rulers or other known objects.”

Doesken’s Colorado Climate Center at Colorado State, working in tandem with the four National Weather Service offices that serve Colorado (Boulder, Pueblo, Grand Junction and Goodland, Kan.), have developed procedures for documenting hailstones including how to get a good photo, measure the maximum diameter and circumference, preserve the stone and contact appropriate officials. For instructions, examples and contact information, go to

In the meantime, Doesken encourages volunteers who observe large hail in Colorado to first report to the National Weather Service or to local law enforcement agencies. The National Weather Service can convey reports of damaging hail to a wider audience through National Weather Service alerts. Large-hail reports provide valuable ground truth which will be helpful for issuance of additional warnings.

“When it’s safe to go out again, retrieve the largest stones and freeze them as soon as possible to avoid further melting,” Doesken said. “Use a ruler to get an accurate measure of the diameter and a flexible or strong tape or string to measure the circumference. If an accurate scale is available, weigh the stone. Preserve the stone by tightly wrapping and sealing it in an air-tight bag.”

If the stone is 4.5 inches in diameter or greater, contact the Colorado Climate Center at (970) 491-8545 or
People who have kept hailstones in their freezer will be disappointed to know the stones lose mass over time, Doesken said. Even if they are tightly wrapped, the ice structure changes with time. But changes will occur more slowly if they are sealed up air tight.

Doesken got the idea for a hailstone repository while he was a member of the executive committee of American Association of State Climatologists. Several neighboring states including Nebraska, South Dakota and Kansas have established new records in recent years. A stone that was eight inches in diameter fell in Vivian, S.D., on July 23, 2010 – almost the size of a football. For more information on that stone, go to

“I don’t believe Colorado has ever had hail that big – and I hope we never do,” Doesken said. “But stones don’t need to be that big to cause damage.

You can really get pummeled with stones that are 1 inch in diameter. Even golf-ball sized hail, which most people don’t realize is nearly 2 inches in diameter, can do serious damage. Crops and gardens can be badly damaged by hail that may only be pea-sized.”

“The motivation has been that other states have been establishing these repositories and Colorado should have done this long ago,” he said. “If you’re going to get hit with something that big, you might as well take some credit for it.”

Doesken has been tracking hail data for more than 30 years. Fort Collins was one of the locations hit with 4.5-inch diameter hail on July 30, 1979.

In 1998, Doesken established a volunteer precipitation monitoring network in Colorado known as the Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS. The network is now in all 50 states with more than 15,000 volunteers. Data from the volunteers improves precipitation monitoring and helps provide detailed storm analysis, drought, water supply and other water decision-making information to municipalities, homeowners, industries, utility providers, resource managers and educators. The program continues to seek volunteers. To volunteer, go to

Guide for hailstone size (diameter measurement listed)

Ping pong ball – 1.5 inches
Golf ball –1.75 inches
Tennis ball – 2.5 inches
Baseball – 2.75 inches
Hockey puck – 3 inches
Softball – 4 inches
Grapefruit – 4.5 inches
CD/DVD – 4.75 inches

Denver Water, et al: A historic moment for Colorado water — Signing of historic agreement for cooperative water management and supply


Here’s the release from Denver Water (Stacy Chesney):

WHO: Governor John Hickenlooper; Grand County Commissioners James Newberry, Nancy Stuart Gary Bumgarner; Penfield Tate, Denver Water Commissioner; Summit County Commissioners Dan Gibbs, Karn Stiegelmeier; William J. Baum, Clinton Ditch & Reservoir Co.; Eric Kuhn, Colorado River District, General Manager.

WHAT: Leaders from Grand County, Summit County, Denver Water and the Clinton Ditch & Reservoir Co. will sign the Colorado River Cooperative Agreement. This unprecedented agreement achieves better environmental health for the Colorado River Basin, maintains high-quality recreational use and improves economics for many cities, counties and businesses impacted by the river. The agreement is the result of five years of negotiations.

WHEN: Tuesday, May 15, 2012, noon

WHERE: Grand County Administration Building, 308 Byers Ave., Hot Sulphur Springs, CO 80451

More Colorado River Cooperative Agreement coverage here.

Denver, Aurora along with Colorado Parks and Wildlife are cooperating to maintain a rainbow trout spawning reach below Eleven Mile Reservoir


From the Aurora Sentinel (Brandon Johannson):

…because of an agreement between the two water departments, state wildlife officials say the future of the rainbow trout population in that stretch of the South Platte — one of only two natural rainbow fisheries on the river — is much brighter than it was a few years ago.

Under the agreement between Parks and Wildlife, Aurora Water and Denver Water, the three agencies are working together to make sure stream flows in the Platte remain constant during the critical spring spawning season.
Regulating the flows in the canyon required Aurora’s and Denver’s help because flows there are largely determined by the water departments’ decisions upstream. Denver Water owns Eleven Mile Reservoir, which flows into the Platte, and Aurora owns Spinney Mountain Reservoir, which feeds Eleven Mile. Because it is a designated “drought reservoir,” the output from Eleven Mile into the Platte is based on what Aurora dumps from Spinney. If Aurora dumps too much, the Platte moves too fast and the young trout are rushed downstream just as they emerge from the egg. If the water level drops too quickly, fertilized eggs could be exposed and dry up on the banks…

With a pile of numbers in hand, Spohn approached Aurora and Denver and asked them to maintain a steady flow during some crucial times. If the river could stay at about 75 cubic feet per second, it would be ideal for spawning, he said. But job No. 1 for Aurora Water and Denver Water is making sure when someone turns on their tap or their sprinkler, a steady stream comes pouring out — regardless of what that means for trout in the canyon. Sometimes that means more than 75 CFS, often as much as 200 CFS. “We can’t operate to the detriment of the citizens of Aurora,” said Brian Fitzpatrick, water resources manager for Aurora Water…

And while Spohn’s focus is on improving the trout fishery in Eleven Mile Canyon, he knows that’s not Aurora’s chief concern. “Wildlife understands that Aurora’s job is to provide water to their customers in the city,” he said. That’s where Denver Water comes in. When Aurora slows the flow from Spinney — often to levels well below what the city needs — Denver Water steps in and loans Aurora some water from Strontia Springs Reservoir. As soon as flows can be bumped up again, Aurora pays back Denver with water from other storage.

More South Platte River basin coverage here and here.

Snowpack/drought/runoff news: Dillion Reservoir at 94% of average, Green Mountain Reservoir = 59%




Click on the thumbnail graphics for the current statewide snowpack map, the Yampa/White Basin High/Low graph and the Gunnison Basin High/Low graph from the Natural Resources Conservation Service.

From The Aspen Times:

Some long-range forecasts call for a wet July and August following extremely dry weather in May and June — which is why Denver Water officials are using a mid-range forecast to dictate their management decisions. Still, others take a more cautious approach…

Dillon Reservoir is just one of the municipal water provider’s storage units, but it will be affected, said Bob Steger, manager of water resources for the utility. Typically, the South Platte River is the go-to source for Denver’s water, but though the basin fared better with snowfall than the Colorado River basin, it wasn’t by much. Even with modest forecasts, the Dillon Reservoir is expected to drop below Frisco Bay Marina’s operating levels — causing it to anchor docks in the deeper water to maintain customer service. Estimates are a drop of as much as 25 feet by September. Downstream from Dillon Reservoir, Green Mountain Reservoir is 59 percent full. Dillon Reservoir is 94 percent full. The average is 84 percent full.

From the Summit County Citizens Voice (Bob Berwyn):

A flow management program [ed. Arkansas River voluntary flow program] developed in the 1980s serves as a statewide model for cooperative agreements on how to meet recreational, environmental and municipal and agricultural needs during years when water is in short supply. White said he’s hopeful the stakeholders will be able to make the agreement work to the benefit of boaters this year…

The voluntary flow program was crafted in the 1990’s by what is now Colorado Parks and Wildlife, Colorado Trout Unlimited, the Southeastern Colorado Water Conservancy District, the Colorado Department of Natural Resources and the Arkansas River Outfitters Association. Administered by the Bureau of Reclamation, the Flow Program provides water management guidelines that benefit the fishery and provide for whitewater flows in the Arkansas River for recreation users, including commercial outfitters and private boaters, in the spring and summer months. Meetings throughout the month of May will help determine how much water municipalities and other water managers will be able to contribute to this year’s program.

From the Longmont Times-Call (Scott Rochat):

On Wednesday, it was time for Firestone’s town board to take up a dry topic — namely, the town’s drought management plan. Still in its draft stages, the plan would allow for restrictions if Firestone’s water supply slips below 110 percent of its demand. The restrictions could deepen further if the water supply reaches genuine shortages, getting below 100 percent or 90 percent of demand…

Both Steve Nguyen of Clear Water Solutions (who prepared the draft) and town manager Wes LaVanchy said it was good to see the town developing a plan ahead of a drought…

The plan soon will be available on the town’s website, Public comment on the plan will be taken for 60 days, beginning today. A preliminary version, which will receive some minor editing this week, is already on the site in the town board’s packet; click on “Town Board,” “TB Agenda/Packet” and then “Meeting Packet.”

From The Valley Courier (Ruth Heide):

Colorado Division of Water Resources Division 3 Division Engineer Craig Cotten reported to members of the Rio Grande Roundtable on Tuesday that the Rio Grande Basin snowpack is about 18 percent of average right now. He said the basin is about a month early as far as runoff. Many of the rivers have already peaked or are at their peak this week. “It is not looking real good,” he said.

He added that the Natural Resources Conservation Service (NRCS) forecasts for both the Rio Grande and Conejos River systems dropped significantly from April to May. Last month the NRCS was predicting an annual flow for the Rio Grande of 465,000 acre feet. This week that forecast was down to 380,000 acre feet…

Of the forecasted flow, 93,200 acre feet must be delivered to the state line to meet Rio Grande Compact obligations. A large portion of that has already been delivered or will be delivered through the winter months, so the current curtailment on the Rio Grande is only 2 percent.

On the Conejos, the current curtailment is 0 percent, Cotten said. He said the Rio Grande Compact obligation to downstream states on the Conejos will be met with what has been delivered so far and what will be delivered after the irrigation season ends this winter, “so we don’t need to curtail ditches on the Conejos system at all to get water to the downstream states.”

The NRCS forecast for the Conejos River system also declined from April to May, he added. In April the NRCS predicted 215,000 acre feet on the Conejos, and this week the forecast was only 180,000 acre feet, about 54 percent of the long-term average.

From the Summit Daily News (Janice Kurbjin):

“The long-term weather forecast is for warmer, drier weather in the foreseeable future,” said Troy Wineland, the district’s new water commissioner. “The picture isn’t altogether pretty at the moment.” Wineland was one of the speakers at Tuesday’s State of the River, an annual meeting hosted by the Colorado River District and its partners. Blue River Watershed Group helped to put on the Summit County event. It’s held every spring to give citizens a chance to understand what’s happening in their watershed, the demands on water resources, and projects that are underway to facilitate water management…

Listeners at the State of the River annual meeting suggested Denver Water officials raise the drought stage to stay ahead of the problem. “It’s not good enough,” said Matt Wade of Ten Mile Creek Kayaks in Frisco. “If we don’t have a crystal ball, shouldn’t we be proactive and have stricter water regulations in Denver to play it safe?” His comment was met with a smattering of applause.

“The philosophy of our drought response plan are that our actions are commensurate with the situation,” [Bob] Steger said, adding that Denver Water board members may choose to heighten the alert, but that hasn’t happened yet.

From the Sky-Hi Daily News (Tonya Bina):

Snowpack measurements for the Upper Colorado basin are the lowest in 45 years, according to the latest Natural Resources Conservation Service readings. At 21 percent of average, the Upper Colorado is at 6 percentage points lower than the previous record set in 2002. The “melt-out at many sites in Colorado this year has been four to six weeks earlier than normal,” states a May 1 Colorado Water Supply Outlook Report produced by the Natural Resources Conservation Service. “It is likely that, barring well above-average spring and summer precipitation, peak flows have already occurred in many basins,” the report reads…

…Eric Kuhn, general manager of the Colorado River District, cautions Front Range and West Slope utilities not to be “lulled into inaction by relatively good reservoir storage,” according to a Colorado River District April newsletter reporting on the district’s quarterly board of directors meeting.

“One of the lessons of 2002 was that municipal users of West Slope water were slow to recognize the drought that year and institute watering restrictions,” the newsletter states, paraphrasing Kuhn. “The result was that reservoirs were hit hard that summer before restrictions were implemented, putting the utilities in a poor storage position for the ensuing year.”

The majority of the state’s streams and rivers are poised to produce just 20 to 40 percent of average volumes during the high water-demand season.

‘Whenever there is a rate increase, our engineers tell us you can expect a 3 to 5 percent drop in demand’ — John Hier (Rifle City Manager)


From the Rifle Citizen Telegram (Nelson Harvey):

The project, which has been under discussion for more than six years, is motivated by the fact that the city’s Graham Mesa Water Treatment Plant is 32 years old and near the end of its useful life. The plant, city officials argue, can’t support Rifle’s growing population, or meet potential new federal water quality standards. Yet in opposing the project, [John Steele] has claimed the rate increases required to fund it would lead to a drastic drop in water demand, depriving the city of the revenue it needs to finance its loan.

Under the rate structure approved by City Council to fund the plant, water rates would rise by about 64 percent for those using up to 2,000 gallons a month, and roughly 99 percent for those using up to 4,000 gallons. Rate increases would be higher if voters do not approve a half cent sales tax increase to help fund the project. “No one has told me whether they can cover the loan with a 20 percent drop in water consumption,” said Steele, which he said could result from the rate hikes…

But City Manager John Hier, who helped design the new rate structure, said there is no way to tell how much demand would drop in response to higher water rates. His plan, he said, accounted for the fact that higher prices would prompt some consumers to use less water. “Whenever there is a rate increase, our engineers tell us you can expect a 3 to 5 percent drop in demand,” he said. “Of course, that depends on how large the increase is, but we were conservative in estimating the rates that would generate enough money to fund the new plant.” Hier said he didn’t know how much consumption would have to drop before the city would be unable to repay its loan.

More infrastructure coverage here.