Microburst Blamed for Damage at SHS Construction Project

Construction crews associated with the addition and renovation project at the Seminole High School campus began cleaning up damage this past weekend left behind from a Sept. 13 thunderstorm.

A storm which resulted in the a partially collapsed back wall for the campus' soon-to-be 900 seat auditorium stage area, as well as twisted and tangled scaffolding associated with the construction project.

"There will be some delays with that portion of the project," said Doug Harriman, Superintendent of Schools for Seminole ISD in an interview with the Sentinel late last week. "But, as for the rest of the (SHS addition/renovation) project, no other damages were reported and construction should continue at the campus as normal."

Harriman said officials with M.W. Builders of Texas, who is serving as the Construction Manager-at-Risk for the SHS project, had their builder's risk insurance company -- Traveler's Insurance -- and a third party engineer on site recently to evaluate the damage.

"It was determined that it was a microburst that caused the problem and that the three concrete masonry unit (CMU) walls surrounding the auditorium's theatre area will have to come completely down," said Harriman.

Harriman said he was unaware of any dollar amount of damage associated with the incident, citing that the issue was between M.W. Builders and their insurance company.

"At this time, it looks like this portion of the project could be about 60-to-90 days behind schedule, at a minimum," said Harriman.

A microburst, according to a definition from the National Weather Service: is a downdraft (sinking air) in a thunderstorm that is less than 2.5 miles in scale.  Some microbursts can pose a threat to life and property, but all microbursts pose a significant threat to aviation. Although microbursts are not as widely recognized as tornadoes, they can cause comparable, and in some cases, worse damage than some tornadoes produce.  In fact, wind speeds as high as 150 mph are possible in extreme microburst cases.

Officials with the Midland regional office of the National Weather Service stated their weather monitoring systems -- located two miles northeast of Seminole and at the Gaines County Airport, three miles south of Seminole -- recorded only windspeeds of 45 mph during the storm's presence in Seminole.

"The gusts could have been higher in other portions of town, away from our monitoring system, but that's the best information we have in regard to the wind speeds," said Alexander Lyster, a meteorologist with the Midland regional office of the NWS in a Sept. 16 story produced by the Sentinel.

According to the NWS, there are a handful of factors that cause microbursts to develop, including mid-level dry air entrainment, cooling beneath the thunderstorm cloud base, sublimation (occurs when the cloud base is above the freezing level), and the existence of rain and/or hail within the thunderstorm (i.e. precipitation loading). Some microbursts are driven by a combination of these factors while others may only be driven by one factor.  

Due to this, microbursts can be subdivided into three primary types -- wet, dry, and hybrid. Cooling beneath the thunderstorm cloud base and sublimation are the primary forcing mechanisms with dry microbursts.  

Dry microbursts typically occur with very little precipitation at the surface or aloft, hence the dry type.  Wet microbursts, on the other hand, are primarily driven by entrainment of mid-level dry air and precipitation loading.  

Hybrid microbursts possess characteristics of both wet and dry microbursts.  They are forced in the mid-levels by dry air entrainment and/or precipitation loading and in the low-levels by cooling beneath the cloud base and/or sublimation.

Billed as Phase III of the district's six phase bond project, the SHS addition/renovation project calls for the addition of a new fine arts facility, six educational classrooms, two science labs and administrative offices to the facility, located in the 2100 block of Hobbs Hwy.

Originally budgeted as a $17.54 million project, the SHS project now has a budget line of $28.02 million.

Adjustments to the budget include the addition $6.12 million to the project budget from interest earned on the SISD Bond investment, the addition of $2.83 million from the SISD Bond contingency line item, and $1.17 million from the bond project's Capital Outlay line.

Detailed lans for SHS' proposed fine arts project include an enlarged band and choir hall facilities, a new 900 seat auditorium, six new classrooms for the campus and new facilities for the campus' speech and theatre departments.

The SHS campus is also expected to see an addition of new administrative offices to the north entrance of the SHS campus, renovations so the campus' current kitchen area, and a renovation to the existing SHS administration offices.