Polar Vortex..... Douglas Lowe, CGCS

Polar Vortex - Despite my many years spent watching the Weather Channel I had to look this one up on Wikipedia!

A polar vortex (also known as a polar cyclone, polar low, or a circumpolar whirl^[1] ) is a persistent, large-scale cyclone located near either of a planet's geographical poles. On Earth, the polar vortices are located in the middle and upper troposphere and the stratosphere. They surround the polar highs and lie in the wake of the polar front. These cold-core low-pressure areas strengthen in the winter and weaken in the summer due to their reliance upon the temperature differential between the equator and the poles.^[2] They usually span less than 1,000 kilometers (620 miles) in which the air is circulating in a counter-clockwise fashion (in the Northern Hemisphere). As with other cyclones, their rotation is caused by the Coriolis effect.


As interesting as that all is, the only thing I know is we had some really cold temperatures descend on our small part of the world this week that evidently originated from the North Pole.  Despite the short nature of the cold spell temperatures were low enough to freeze over our ponds and cause water breaks everywhere.  Despite a strong awareness of the risk for bursting water pipes I think the club still had four pipes freeze in various facilities throughout the club. Our low Tuesday night was a record 5 degrees, which beat the old record  of 14 degrees.  The question most golfers who have lived in this part of the world for very long are quick to ask is do you think we will lose any of our warm season grasses?


Bermudagrass
The primary Bermudagrass variety on our two courses is Tifway 419.  Depending on the research you look at cold tolerance ratings range from 15 degrees F to 20 degrees F.  Most of this research is done in a controlled lab setting so there can be a wide range of variations that are actually witnessed in the field but based on past experience we typically see some level of damage when temperatures drop below 15 degrees F for an extended period of time.  The longer the duration then the more damage.  The colder the temperature then the more likelihood for measurable damage.  Our duration was just two days so we've got that working for us.  The fact the temperature dropped to 5 degrees F is what we have working against us.

Zoysiagrass
There are several species of Zoysia in use on our courses but the primary type is Zeon Zoysia, which is on the Farm course.  This strain belongs to matrella species and is classified as having moderate tolerance to low temperatures.  The cold tolerance of matrella species such as Zeon is slightly better than our Tifway 419 with ratings ranging from 16 degrees F to 12 degrees F.  Again, there are a lot of other variables to consider such as duration, drainage, and shade that will all affect how much cold weather a particular grass or an area of grass can withstand.


What does it all Mean?
What this means is with the record low of 5 degrees we recently experienced there is a real potential for some areas of grass throughout both the two courses to demonstrate some level of damage in the spring.  On the flip side, just because temperatures dropped below cold tolerance ratings does not mean that healthy turf will show any signs of damage.  It means we will need to be proactive with our first quarter expenses until we have a better idea of what we may be facing.  It means we need to wait and see if we have any additional cold weather anomalies that affect our region over the next two and half months.  In the end it means as of today we don't know or expect anything for sure.  Even if the plant was damaged it will take at least 6-10 weeks to deteriorate and develop symptoms that are visible.  All we can do know is hope for the best and plan for what could be.  If the remaining part of the winter season is closer to average or typical I think we will be O.K. except for some of the worst shady or wet areas,which is fairly typical.  If we get another round of cold weather later in the season when the grass has depleted all it's stored energy and it's defense mechanisms are weaker then we will definitely be looking to replace some turf.