By Matt Nelson
Winter injury to putting greens can affect playing conditions
at high elevation or northern golf courses for an entire season.
Experienced golf course superintendents and course officials
usually will try to implement every reasonable precaution
possible to limit the potential for winter damage, but specific
weather conditions may, and often do, thwart the best
preventative programming. While there are no guaranteed methods
to prevent winterkill on golf course turf, late winter/early
spring snow removal has become widely practiced at moutainous and
northern golf courses to help prevent damage associated with snow
and ice cover. Sans the slide guitar of Joe Walsh, this article
will address snow removal practices the
Rocky Mountain Way
Winterkill of putting green turfgrass usually occurs as a result
of desiccation, disease, or freeze injury. Of these, freeze
injury is typically the most difficult to prevent. Freeze injury
may occur from exposure to lethal temperatures without snow cover
or other insulation when ice crystals form within and around
cells of meristematic tissue. During freeze/thaw events, water
may be drawn out of plant cells as ice crystals form around them,
causing dehydration and membrane collapse. Mitigating damage from
the latter form of freeze injury usually is accomplished by
limiting surface moisture in late winter or early spring by
removing snow and ice.
|Shovels may be necessary to get the final
few inches of snow off of a green.|
DON'T REMAIN IN THE DARK!
There are three factors commonly associated with freeze
injury: shade, poor surface drainage, and significant populations
(annual bluegrass). Removing trees, adjusting grade or design,
and establishing creeping bentgrass are successful methods of
reducing the potential for winter injury associated with
plant spruce or other evergreen trees within 125 feet to the
southeast, south, or southwest of greens. This is a recipe for
eventual disaster at northern locations where extensive shade
will be cast when the sun angle is low during winter months. If
evergreen conifers already exist in the aforementioned proximity
of putting greens, cut them down.
Shade in the late summer and fall limit a turfgrass
plant's ability to achieve maximum winter hardiness by
compromising photosynthesis necessary for energy fixation and
carbohydrate storage. Stored energy enables a plant to tolerate
cold temperature exposure and maintain hardiness for a longer
period of time, which is critical to survival during freeze/thaw
events of late winter or early spring. Shade during the winter
prolongs snow and ice cover and may cause more freezing events.
Shade during spring delays soil warming necessary for growth and
recovery. Shade will exacerbate winterkill problems on greens
with a northerly slope aspect. Snow removal alone will not
consistently prevent winter injury to shade-affected greens;
thus, allowing for sunlight penetration is an important component
of winter turf survival.
PULLING THE TRIGGER
Removing snow and ice from putting surfaces involves
experience with the site and local climate conditions, judgment,
and some confidence in the weather forecast. At most sites across
the Rocky Mountain region of the U.S. (and high-elevation sites
in the Sierra and Cascade mountains), this will occur in early to
mid/late March. Snow provides insulation that buffers turf from
temperature extremes; thus, removal too early may expose the turf
to lethal cold temperatures or unseasonably warm temperatures
that cause a rapid loss of winter hardiness and potential damage
if temperatures drop again significantly. Ice layers that form
early in the winter pose a unique challenge, since relatively
little is known about the factors contributing to turf failure
under ice, including the condition of the turf when ice formed,
ice composition, and how long the turf can safely tolerate ice
cover. Creeping bentgrass will tolerate ice much better than
annual bluegrass. Some superintendents have removed an ice layer
in midwinter and blown snow back onto the greens to provide
On the other hand, waiting too long to remove snow can result
in increased disease activity and expose turf that has already
broken dormancy. Regular monitoring of turf through the winter is
a good idea as a method to gauge its condition and also help
determine when to remove snow. Dormant turf will be more tolerant
of cold night temperatures once snow is removed.
Most turf managers implement late winter snow removal when the
weather forecast calls for melting temperatures and sun. Although
severe weather may still occur, the likelihood of extreme cold is
at least lower as spring begins. Favorable weather allows turf to
gradually break dormancy as the days begin to warm. The benefits
of removing snow from putting green turf include the
. Reduced turf exposure to melting snow and ice and less
chance of freeze injury.
. Enhanced disease control at sites with extended snow cover.
Disease prevention products may begin to lose efficacy after many
months, and additional applications are usually made following
. The turf can begin growth and/or recovery if favorable
weather conditions occur. This can be valuable if winter injury
exists, often a result of rapid and/or severe freezing in fall
without ample hardening time.
. Some golf course superintendents will conduct core
cultivation at this time of year to minimize disruption to
golfers. This typically requires plenty of available labor, a
means to transport cultivation equipment to greens, permeable
covers to accelerate warming and recovery, and decent
A myriad of snow removal tools and practices can get the job done
effectively. At most mountain golf courses, large,
tractor-mounted snow blowers are used to clear deep snow packs to
within a foot or less of the putting surface. These same machines
also are used during the winter to clear paths to the greens for
monitoring and access when snow removal is initiated. Smaller,
walk-behind snow blowers can then be used to more safely remove
snow closer to the turf. Shovels will take care of the rest if
rapid melting is not likely. Keep these tips in mind for optimal
|Tractor-mounted snow blowers, walk-behind
snow blowers, and green covers are tools commonly used to
remove snow from greens and safeguard turf health in the
. Set poles or other marking devices in the fall to delineate
putting green perimeters and abrupt contours, bunkers, streams,
etc. Marking will help avoid mechanical injury when blowing or
plowing snow, and it will indicate that removed snow is far
enough from the green to not obstruct surface drainage. Clear
snow far enough from the greens to prevent snow on banks from
melting back onto the greens or cause a shade problem if the
banks are high enough. Avoid burying sprinkler heads or
. Have at least one person probe the snow pack out in front of
the blower or plow to help the equipment operator gauge depth
. Start snow removal early in the morning or on cloudy days
when the snow is cold and firm. The snow will be lighter and can
be blown away more easily from the green. Working while the turf
is frozen also will reduce the potential for mechanical injury.
Use warm afternoons to remove snow from tees and cart paths.
. Finish removing as much snow as possible from one green
before going on to the next. Use small, walk-behind snow blowers
after using larger equipment. Use shovels to remove remaining
snow to the extent possible. Snow that is not removed will set up
and become very firm and more difficult to remove than with the
first attempt. At the least, cut paths for surface drainage off
of the green.
. Darkening agents, including colored sand, compost, humates,
or fertilizers, can expedite melting of the final inches of snow
and ice. The more inert the product, the better.
. Realize that snow may need to be removed several times in
. Monitor the greens closely after they are cleared. Any
standing water on the greens in the afternoon may freeze and
could damage the turf. Use shovels or roller squeegees to
. Keep an eye on soil moisture between snow removal and
activation of the irrigation system. Covering may be helpful, and
snow can be added to high spots or crowns to prevent desiccation.
Charge the irrigation system as early as possible and hand water
. Sleds may be useful to haul mowers, spreaders, aerators,
etc. out to greens cleared of snow while a significant snow pack
remains across the rest of the course.
. Don't be afraid to damage the turf. A few nicks and
dings will be easier to repair than widespread turf loss from
disease or freeze injury.
Although snow removal from putting greens is a common practice
at golf courses throughout the Rocky Mountains with significant
snow pack, clearing the greens does not guarantee that winter
injury has not or will not happen. This program, however, does
appear to increase the chances of turf survival and accelerate
growth and recovery in most years. Improved winter management
techniques, including snow removal, covering, disease control,
winter watering, sunlight assessment, turfgrass renovation, and
drainage, have helped reduce springtime crying that the greens
are bad, and modern winter management in the Rocky Mountains is
better than it used to be.
Happ, K. 2004.Winter damage. USGA Green Section Record.
Skorulski, J. 2003. The greatest challenge. USGA Green Section
Record. Sept./Oct. 40(5):1-6.
Snow, J. 1980. Putting greens: Dealing with snow and ice
accumulations. USGA Green Section Record. Jan./Feb.
Vavrek, R. 1994. Have an "ice" day. USGA Green
Section Record. May/June. 33(3):17-18.
Special thanks to USGA Green Section committeeman Derf Soller,
CGCS, from the high country of Colorado for several of the
useful tips found in this article.
Matt Nelson is Senior Agronomist in the Northwest Region of
the Green Section.