November 30, 2011

Wind warning system helps limit damage in Calgary

RICHARD GILBERT

staff writer

A wind warning system designed to predict major storms helped the City of Calgary warn contractors at highrise construction sites before high winds damaged the downtown core.

“The wind warning system has been implemented and we received data from the system four hours before we received a warning from Environment Canada,” said Bruce Burrell, director of the Calgary Emergency Management Agency (CEMA).

“We have received some previous data from the system, but this was the first significant test.”

Calgary was hit hard on Nov. 27 by winds of 60 km/h and gusts up to 120 km/h. The winds caused a lot of damage, by downing more than 100 trees, and power lines, and shattering highrise windows.

“One of the nice features of the system is we get data for gusts of wind at different height levels, while with Environment Canada data we just get ground speed,” said Burrell.

“As a result of both reports indicating the same type of weather pattern, it allowed us to get information out to our membership 22 hours before the actual peak wind.”

In response to high winds and resulting damage across the city, CEMA activated the Municipal Emergency Plan at 1:05 p.m. on Nov. 27.

“The wind warning system definitely had a positive effect on the final result,” said Kevin Griffiths, Calgary’s chief building official.

“We focused our efforts for the initial roll out of the system in the downtown core, where there was the highest risk. There was not one report of debris leaving a single building under construction this weekend. The debris was material coming off existing buildings.”

Reports of wind related damage came in from all over the city.

For example, at 12:02 p.m. on Nov. 27, the wind ripped the roof off and smashed windows out of a residence in the 100 block of Slopes GV SW. At TD Square, several large windows were ripped out and a vehicle was damaged from falling glass.

The highest winds were clocked at 149 km/hour, equivalent to the force of a Category 1 hurricane. This was recorded on top of the under-construction Bow tower.

Police urged residents to stay indoors as flying debris was a hazard on roads and walkways.

Toppled trees hit power lines and crushed cars. Shingles flew off roofs.

High winds even ripped off three LRT crossing arms, causing delays.

Falling shards of glass cut one firefighter and damaged a vehicle, but there were no reports of any major injuries.

The downtown was shut down as a safety precaution and every fire truck in the city responded to downed trees and broken windows.

Police, firefighters, Enmax staff and city workers were scrambling to deal with power outages, felled trees and broken glass.

Enmax had to call in several extra repair crews to help work through a massive backlog of downed lines.

The downtown core was reopened to all vehicle and transit traffic by 4:30 a.m. on Nov 28, except for several streets where building safety assessments were still underway.

“We have one block, that we are working on in the downtown core, which is next to the 3rd Street LRT Station,” said Burrell. “Glass is being dealt with from the building above and debris is still being cleared away.

Assessment teams comprised of Calgary Fire, Calgary Police Service, Development and Building Approvals and Roads assessed the downtown area and carried out clean-up as required.

About 100 city staff hauled away broken glass and debris. Calgary is prone to gusty summer windstorms and in the past few years there have been a number of incidents involving debris falling from downtown construction sites.

After one of these incidents in August 2008, where a threeyear- old was killed by a bundle of steel roofing materials, the local construction industry formed a committee to study improved safety options.

One of the committee’s first actions was to explore the feasibility of engaging a vendor to provide an early warning weather system.

The City of Calgary put out a request for proposal to develop a high-tech early warning system to monitor major weather patterns.

The system was designed to alert construction companies, so they can secure or remove building materials and equipment.

The winning response came from Rowan Williams Davies & Irwin Inc. (RWDI), an engineering consulting firm.

RWDI was awarded a $240,000 contract for the first phase of the project, which involves software development and the use of the system for one year.

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