Even resorts that offer activities all year depend on a good ski season for economic success. Indeed, the livelihoods of many people, working not only at the ski areas but in the surrounding communities as well, are dependent upon the economics of a successful winter sport season.

Prior to the 1950s, Mother Nature alone determined the length and quality of the ski season. Then people learned how to make 'snow'. Now, snow-making technology and practice has advanced, allowing ski areas to open sooner and close later than ever before.

Even snow making, however, depends on suitable weather conditions. You still can't make snow when the temperature is 40 deg F. The basic process involves injecting atomized water, a mixture of air and very fine spray, into the atmosphere where the tiny droplets freeze, fall and cover the slopes. While the freezing process depends mostly on the ambient temperature, it is hastened by the partial evaporation of the tiny water droplets, which removes a substantial amount of heat from the cooling droplet prior to its conversion to a snow crystal. Evaporation, in turn, depends on the relative humidity. If the humidity is too high, evaporation cannot proceed quickly enough to promote the freezing process.

There are many combinations of temperature and humidity that provide good, bad and average snow making conditions. Wind speed and direction are also important factors. Generally speaking, temperatures should be in the mid 20s or lower. (Extreme cold, however, will adversely affect pipes and other equipment.) A temperature in the mid 20s should be accompanied by a relative humidity of 60% or less. As the temperature gets lower, then higher humidities can be tolerated.

And where does the wind fit in? There's the obvious consideration of where the new 'snow' will fall, which determines the placement and aiming of the snow guns. Another wind speed consideration involves the need to change the air. As mentioned earlier, the tiny droplets evaporate somewhat when injected into the atmosphere. This causes the relative humidity of the air to increase in the droplet cloud. If the wind is calm, the air will soon become 'saturated', further evaporation will be almost impossible, and the snow making process deteriorates. Thus, it is very important that there is at least some wind to carry the moist air away and replace it with dry air.

Slopes with large vertical drops can be affected by very different weather conditions at the top versus the base. Wind direction, wind speed, temperature and relative humidity can all vary substantially from top to bottom. This can limit the locations at which snow can be generated to a particular slope or elevation. It might even be necessary to create snow in one area and later move it to slopes that need additional coverage.

Obviously, ski area operators have plenty to think about when they wish to make snow. Once they consider the weather conditions, there can be extensive activities preliminary to the actual snow making. Depending on the type and age of equipment, preparations could include adjustments of water, compressed air, and nozzles to optimize the quality of the 'snow', and adjusting the aim so the snow falls in the right places. People have to be mobilized. Compressors and pumps must be fired up. There may be activities peculiar to the slope itself. In short, there's a lot to do! You don't just turn these babies on and off like a light switch.

In some cases, the hassle and expense of making snow tonight is unnecessary, because Mother Nature will come through with plenty of the white stuff tomorrow.  We can tell you when that will happen, too.

By now it should be perfectly clear that ski area operators need help from professional, experienced forecasters, like those at the Skywatch Weather Center. We issue custom forecasts, usually twice per day, detailing all the conditions that operators need in making their decisions. As necessary, we differentiate conditions from base to top, and each forecast is tailor-made for the precise location of the individual ski area. Delivery is available via fax, computer-to-computer, dial-up and the Internet. A menu of national and regional graphics are available free of charge to customers only via our home page. Of course, customers can call us toll free for one-on-one consultations with a forecaster anytime critical decisions hang in the balance.


Professional consultants at Skywatch help each individual park develop a custom weather program, addressing precisely the needs of the park's various managers and supervisors. There are so many different types of parks scattered across so many different climatological regions of the country that there are many different reasons for needing accurate weather forecasts. The following suggestions are just a few examples of things that parks can do with advance knowledge of weather conditions. (You park managers out there could probably think of a hundred more, and we'd be delighted if you'd e-mail us some of your examples.)

Weather features of importance to all parks are those that can cause damage and injury. Lightning strikes threaten any outdoor activity, but water parks are especially dangerous during thunderstorms. High winds require shutting down many elevated rides, from roller coasters to Ferris wheels to sky coasters. Heavy rainfall can cause dangerous conditions on many rides due to slippery conditions and inconsistent friction between the car wheels and the ride's support structures. Hail associated with severe thunderstorms can cause personal injury to those caught unprotected.

Skywatch diligently watches for conditions that could produce severe weather at its customers' exact locations. An 'alert' is normally issued 12 to 24 hours ahead of the threat. This 'heads-up' provides a general description of the expected severe weather and the approximate timing of the event. A 'warning' is issued three to six hours in advance, detailing the nature of the threat and providing more precise beginning and ending times. A final notification is usually made 20 to 30 minutes before the storm hits, giving park personnel and visitors just enough time to do whatever they have to do to protect the park equipment and customers. This very valuable service can make a big difference in the degree of property damage and reduce or eliminate personal injuries.

Delivery of our forecasts is done via phone, fax, computer-to-computer, dial-up and Internet, and a menu of national and regional graphics at our home page are available free of charge to customers only. Of course, customers can call us toll free to speak directly with a forecaster when the time for a critical decision nears.


Very few baseball games are cancelled these days due to rain or thunderstorms. Much of the credit for this is related to the design of drainage systems under both artificial and natural turf fields. Automatic tarp systems allow covering and uncovering the infield, and vacuums suck off excess water to get the field back in working order in a very short time. Still, using these measures always means anticipating when the rains will start and end. If the field crew removes the tarp during a lull in the rain, and a 15 minute cloudburst dumps a half inch of rain on the field, it could threaten using the field for the rest of the day or cause a substantial delay to rehabilitate the field for action when the rains do stop for good. If it has been raining all morning, should the team cancel the game early enough for the public to stay at home? Can they delay the start and still get in the full nine innings?

Skywatch Weather Center keeps track of the weather and will advise the club exactly what can be expected on a game day, based upon real-time radar evaluations of the present conditions, and the forecast of conditions expected throughout the course of the game. We are watching the specific location of the ballpark, for pinpoint accuracy of each rain event.


Many amateur and professional golfers love to play on the lush fairways and manicured greens of their local courses. Knowing when Mother Nature is going to water the course can save money, because running the sprinkler system can use tremendous amounts of water. Weather services can forecast when the natural stuff is going to fall, and how much. This aids the course manager in maintaining the health of the turf, and especially the greens. They are more susceptible to burnout than a normal lawn. Because the greens have to be cut to a very short level for optimal play, they don't have the resistance against drying that a longer grass blade might have.

There is a risk when thunderstorms rumble through, as lightning strikes can fatally strike a golfer. Lightning strikes normally occur to the highest exposed point in an area. The open expanses of a golf fairway can easily turn a player wielding a metal club into the equivalent of a lightning rod.

Skywatch Weather Center provides warning in sufficient time for the course managers to notify players and get them to shelter. While most thunderstorms are heralded by rumbling thunder in advance of the rain and lightning strikes, there is still the possibility of strikes far ahead of the main storm. On the other hand, the rumbling of thunder doesn't necessarily mean the storm is going to hit the course. Skywatch forecasters, tracking the storm on radar, know whether it will hit or miss a specific area, and they will warn course operators accordingly.


For more information contact our webmaster or call us at 1-800-SKYWATCH  1-800-759-9282

Copyright © 2007, Air Science Consultants, Inc.