Flash flood preparedness tips

Floods can happen in a flash: If creek levels suddenly rise or fall, move to higher ground and call 911.

Stay alert: Monitor the weather, watch water levels in creeks, look for shifting landscape formations or structures.

Be ready to respond: Make an emergency plan in advance. Choose an emergency contact. Designate safe meeting places.

Get emergency updates: Get emails or text messages by signing up at boco911alert.com.

Buy flood insurance: Visit floodsmart.gov or call 888-379-9531 for more information. Boulder residents may be eligible for a discount.

Protect your property: Adjust downspouts and prevent floodwaters from entering through window wells, doors and other openings.

Know your neighbors: Collect your neighbors' contact information for emergency situations.

Prepare for basement flooding: Consider buying a sump pump and test your dewatering system.

For more information: boulderfloodinfo.net

Source: City of Boulder

Boulder Office of Emergency Management:

boulderoem.org

The heavy rains and scattered thunderstorms in Boulder County over the weekend gave emergency officials a taste of what may be coming during flash flood season this summer.

With the ground still heavily saturated from September's floods, the rain that fell off and on for multiple days last week pooled in underpasses, streets and drainage areas, and it gave residents of the area burned in the Fourmile Fire of 2010 a short-lived scare.

Ultimately, emergency officials said the storms didn't cause any significant destruction and allowed them to test their plans ahead of what's sure to be another busy flash flood season in Colorado.

"More runoff, less absorption into the ground — those factor into what we're looking at," said Boulder Office of Emergency Management director Mike Chard. "We get storms happening and saturation and multiple-day events of rain; of course, that increases the concern."

At about 8:20 p.m. Friday, emergency officials made reverse-notification calls to people in part of the Fourmile burn area, and the National Weather Service warned residents to move to higher ground. Officials lifted the warning half an hour later.

Several underpasses in Boulder were still closed Tuesday because of localized flooding and standing water, though city officials said that's a common occurrence this time of year.

"If anything else, what the weekend has done is it's allowed us to test all of our new plans, our new procedures and see how they worked," Chard said. "They seemed to hold pretty well."

That office has been fine-tuning new flood response plans since the Fourmile Fire in 2010, Chard said.

Some of the localized flooding in streets and private driveways that occurred last weekend could have been caused by small debris leftover from September's floods, officials said.

Boulder County transportation crews cleared debris from culverts over the weekend, and they worked on a low spot on Longmont Dam Road on Tuesday, said county transportation spokesman Andrew Barth.

County crews worked constantly this winter to remove large hazardous debris from creeks and drainage areas, and that work paid off, Chard said, though there were a few issues that crews weren't able to predict until the latest thunderstorms passed over.

Chard said there was some rock movement up Boulder Canyon near Sugarloaf Mountain that crews cleared quickly. There was also some bank erosion along the North and South St. Vrain creeks that caused one tree to fall over and a few others to almost fall over, he said.

In Lyons, officials closed McConnell Road on Saturday night because of erosion.

"There was some frequency of something happening in the creeks and rivers, but they were very minor in severity, and we hope that holds and continues," Chard said. "They weren't going to show themselves until (weather events) happened."

Flash flood season officially began April 1 and ends Sept. 1, though it's not just local rains and thunderstorms that can cause flooding, Chard said.

Thunderstorms high up in the mountains can cause the snow to melt quickly, prompting spring runoff to accelerate and fill the creeks within the county.

Chard added that extra runoff may also occur because the ground is still saturated with water from September's floods. The water table can stay elevated for a year to 18 months after such a major rain event, Chard said.

All of those factors have led emergency officials to ask residents to be extra vigilant this flash flood season.

"Make sure you're signed up for emergency warnings, have a plan, have a weather radio," Chard said. "Pay attention to the skies; pay attention to the forecast."

Contact Camera Staff Writer Sarah Kuta at 303-473-1106 or kutas@dailycamera.com.