The dilemma with recent extreme temperatures

Karl Danneberger

This past summer was blistering hot. Although the phrase “blistering hot” or “hotter than normal” is rather vague, it’s associated with a temperature record or a personal experience that brings clarity to the terminology.

I could tell how hot the summer of 2020 was by how well my 1969 Pontiac Firebird and my son’s 1970 Chevrolet Nova ran. This summer, we would occasionally go out for a Saturday cruise. As the summer progressed and temperatures rose, the Nova would shut off (vapor lock?). We would wait a few minutes, and then the car would start back up and off we would go — usually back to the garage.

One Saturday in late July, we didn’t get back to the garage. Driving through west Columbus, the Nova stopped. When restarted, the car, within a couple of minutes, was running 30 degrees F hotter than normal. Popping the hood, we noticed the fan was not turning.

Stranded on a side street, waiting for a tow truck while cars drove by honking, is always a unique father-son moment.

One problem was the electric fan’s (what we will do for extra horsepower) location up against the radiator. A car’s fan helps provide a draft of air through the radiator aiding in cooling the liquid. The fan’s diameter did not reach the outer areas of the radiator. Thus, along the edges, the liquid was not cooling sufficiently, contributing to the rise in temperature. One remedy was to add a shroud that helped improve air movement along with the entire radiator.

The lack of a shroud was not an issue when air temperatures were cool, given our driving distance, but at higher temperatures, the lack of one was detrimental. Once the temperature became extremely high, the car ceased to run.

Extreme is an interesting word that means the farthest point from the center. Related to cars, an extreme condition might be looked at as having your car towed. Regarding golf course management, extreme is reserved for temperatures.

During the summer of 2020, the Southwestern United States experienced severe heat waves and temperatures, maybe no more so than Death Valley, Calif. High temperatures are no stranger to Death Valley, but on Aug. 16, 2020, the Furnace Creek Visitor Center weather station recorded a temperature of 129.9 degrees Fahrenheit at 5:41 p.m. PDT. The National Oceanic and Atmospheric Association rounded that temperature to 130 F in its final report.

Only three temperatures of at least 130 F have been recognized by the World Meteorological Organization, including the 130 F recorded this year at Death Valley. The other two are the 131 F recording at Kebilli, Tunisia, on July 7, 1951, and the world record of 134 F at Death Valley on July 10, 1913. By definition, extreme temperatures are those at or above 130 F.

Turfgrasses rarely live in an environment of extreme temperatures. However, as temperatures move further from the optimum range for growth, the potential for plant injury increases. The major cooling system for turfgrasses is evapotranspiration. As the plant transpires, the conversion of water from a liquid to a gas dissipating heat is known as evaporative cooling.

Aiding in the cooling process is the movement of air across the leaf. Slight breezes or winds enhance evapotranspiration. Where natural wind movement across a green is not possible, mechanical fans might generate an artificial breeze. Golf course greens act much like a car’s radiator with a breeze — natural or artificial — enhancing the cooling process. Transpirational cooling reduces the canopy temperature while a breeze aids in cooling.

But, like a car fan — without a shroud — the fan’s effectiveness is only within its radius and dissipates with distance. As temperatures become more extreme, areas outside the fan’s effective range become increasingly more stressed.

This fall is a good time to reevaluate how effective your fans are. What might have worked satisfactorily for a normal year may not be effective in an above-normal year. Adding fans or looking to upgrade a fan’s capabilities will help address temperature stress on putting greens.