O Fair (Dry, Windy, Stormy) New MexicoThis article appeared in the Summer, 1997 issue of New Mexico Resources.
Ask meteorologists to describe New Mexico's weather and they'll you it has a semiarid, subtropical climate with abundant sunshine, gusty winds, little rainfall, and low humidity.
Ask farmers and ranchers to describe the weather, and they tell you about droughts that parched range grasses and dryland crops, hailstorms that flattened a promising year, rains that ruined cut alfalfa, frosts that zapped fruit, winds that sandblasted vegetables, and cold snaps that killed sheep and cattle. Their highest compliment about the weather is, "It wasn't bad."
Whether you see it in scientific terms or watch its effects on a particular crop, New Mexico's weather is variable and extreme. National Weather Service (NWS) records show temperature extremes ranging from -50 to 122 degrees. In a single day, temperature swings of 30 to 40 degrees are commonplace.
Though rain is scant, New Mexico has more than its share of severe weather, including thunderstorms, flash floods, hail, lightning strikes, high winds, and tornadoes. Annual snowfall can vary from less than two inches in southern deserts to hundreds of inches on northern mountain peaks.
"For what many people see as a 'no weather' place, we seem to have quite a bit," notes Keith Hayes, warning coordination meteorologist with the NWS in Albuquerque. During one weekend this spring, Hayes tracked a blizzard in east-central New Mexico; a dust storm with 80-mile-per-hour winds in Deming; and a severe weather system with thunderstorms, hail, and tornadoes in Eddy County.
The unpredictability of New Mexico's weather keeps forecasters guessing and producers watching the skies, the weather updates, and the long-term outlooks. Each year, farmers and ranchers do battle with the elements.
Sun: Measuring an enchanted acre of sunlight
Sunshine makes up the biggest weather commodity in New Mexico, fitting for a state with the ancient Zia sun symbol on its flag. The flag's gold field represents Spanish conquistadors' quest for the Seven Cities of Gold. While the dreams of precious metal never panned out, the state is renowned for its golden sunlight.
Tourism promoters brag about the percentage of sunny days in the Land of Enchantment, second only to Arizona, according to data from the Commerce Department and National Oceanic and Atmospheric Administration.
In a USA Today weather ranking, Albuquerque's 76-percent sunshine helped it break through as one of the nation's 10 sunniest cities. Though only larger cities were included, Las Cruces' neighbor, El Paso, Texas, racked up 83-percent annual sunshine for fifth place. First-ranked Yuma, Ariz., outshone the competition with 90-percent sunshine.
Many southern New Mexican towns claim up to 350 sunny days each year, although Max Blood, meteorologist-in-charge with the NWS monitoring station in Santa Teresa, can't remember a call for sunshine statistics in eight years.
Should someone ask, he can tell them, right down to the minute. Santa Teresa has a "sunshine switch," a simple measuring device that consists of a solar cell surrounded by a ring attached to a clock. Readings taken once per minute provide a rough measure of surface solar radiation.
"Anytime the sun is bright enough to cast a shadow on the cell, it turns the clock on for a minute," Blood explains. "Even with quite a bit of high cloudiness there's enough sunlight to cast a shadow."
At day's end, meteorologists tally the minutes as a percentage of possible sunshine. Measurements taken over the last 30 years show that Las Cruces and south-central New Mexico have 84 percent of possible annual sunshine.
Farmers measure the value of an acre of enchanted sunlight in more down-to-earth terms. Soil temperature is key for optimum planting. Sunshine promotes germination and strengthens tender seedlings.
Converted to heat units and degree days, sunshine affects crop maturity and helps predict when insect populations will peak. Along with wind, sunshine determines the potential evapotranspiration rate used to figure crop water needs and schedule irrigation.
Heat-loving crops like cotton crave the sun, first to warm the soil to the 60 degrees required for planting and then to stimulate boll production.
"Cotton farmers pray for 100-degree weather," says Ted Sammis, state climatologist and hydrologist with NMSU's College of Agriculture, Consumer and Environmental Sciences. Though many other factors affect yields, without the sun it's impossible to make 3-bale-to-the-acre cotton, says Charles Glover, an agronomist retired from NMSU's Cooperative Extension Service.
Sunlight has built New Mexico's growing nursery industry, which now ranks seventh statewide in cash receipts for agricultural commodities.
"Year-round sunshine is our biggest advantage," says Rhett Dodge, a 1996 NMSU graduate who's spent time in cloudy Oregon and Canada and now works for Aldershot of New Mexico, a wholesale nursery in Las Cruces. In southern New Mexico, greenhouses need no artificial light. The dry climate also allows nursery owners to use evaporative coolers in summer and minimal heating in winter.
New Mexico's sunshine has prodded dairies to relocate for similar reasons. "Operators don't have to make the major investment in housing here," says Ron Parker, Extension animal resources department head. "Cows can be maintained in drylot conditions, although they may benefit from shades, misters, and fans to minimize heat stress."
While it's usually welcome, the enchanted sun can sometimes be too much of a good thing.
The state's altitude increases ultraviolet radiation -- the so-called "sunburn factor." Invisible UV rays increase by 4 percent for every 1,000 feet above sea level.
Though they aren't a problem for most crops, UV rays can burn people in minutes and scorch some tender plants.
Aldershot's glass greenhouses have energy curtains to protect nursery stock. When sensors show an overload of UV rays, the computer-controlled curtains roll out to lessen light intensity.
For some vegetables, New Mexico's sun also can be too much of a good thing. Lettuce and onions shrivel in the heat. Though chile plants like hot weather, leaves and pods can suffer from sunscald, particularly if plants are diseased or lack nitrogen.
Even on New Mexico's hottest days, plants, animals, and people get a break after the sun goes down. Temperatures drop rapidly, thanks to the elevation and low humidity. A major advantage of "dry heat" is less water vapor in the air to slow down the nightly cooling process.
Wind: Driving windmills and weather
The opening verse of the state song, "O Fair New Mexico," paints a rosy picture of the state's weather:
Under a sky of azure, where balmy breezes blow;
Kissed by the golden sunshine, is Nuevo Mejico.
Growing up, Parker experienced the drought of the 1950s and modified the song's chorus: "O Fair New Mexico, it never rains, it never snows. The dadburn wind just blows and blows."
Wind blows because of differences in atmospheric pressure, triggering air movement that equalizes the pressure.
On any day in eastern New Mexico, odds are the wind will be blowing. As an extension of the Great Plains, the region lacks the buffering spine of central mountains to deflect wind and storms. Meteorologists say that's why the High Plains has more than its share of wind, hail, and severe weather.
Not surprisingly, six of the nation's 10 windiest cities are in the West. Amarillo, Texas, adjacent to dust-storm-prone eastern New Mexico, gusted into third place behind Blue Hill, Mass., and Dodge City, Kan.
Mountains, a source of "instant weather," attract fast-moving, upper-level storms that bring high winds.
The number of windmills in New Mexico testifies to the wind's power to shape our landscape and lives. "Some of the windmills have been out there for three or four generations," says James Dean, a retired NMSU agricultural mechanics professor who teaches classes on windmill maintenance.
Although it seems an ever-present force, New Mexico's wind is not always reliable. "It's a very dependable source of power for lifting water . . . so long as the wind blows," Dean jokes.
On southern New Mexico's Jornada del Muerto, however, July is a notoriously still month. Elsewhere, wind patterns are less predictable, although several weeks can pass without enough wind to pump sufficient water.
To compensate, ranchers fill huge water storage tanks, rotate animals into areas with water, and install solar-powered submersible pumps or gasoline-driven pump jacks as backup power.
When the wind blows, it often picks up soil, sandblasting crops. The tattered leaves of wind damage resemble the early stages of many diseases, leading Natalie Goldberg, Extension plant pathologist, to ask about wind when she receives plant specimens.
Though it's the bane of vegetables, wind can be a friend to fruit. Some growers head off freezes by stirring up artificial gusts with giant propellers. "For orchards in valleys, the wind machines keep cold air from settling," says Esteban Herrera, Extension horticulturist. "This inverts the layers of cold and warm air, protecting the trees in bloom."
Rain: Counting on the monsoon season
Wind is a powerful force in New Mexico, not only for pumping water but also for shaping the weather. One somewhat predictable event in New Mexico's weather is "monsoon season" in July and August, when most of the rain falls in summer thunderstorms.
Though it may seem a stretch to talk about a monsoon in the desert, the term actually has more to do with wind than rain, Blood says.
"When you grow up, in school you learn about the monsoon season when they have tremendous rains in India," he says. "But monsoon does not refer to rain per se, but to the reversal of flow that brings an increase in moisture."
When the wind changes direction during monsoon season, it sets up a southerly flow of moist air, which condenses over land and falls as rain. In New Mexico's case, the monsoonal flow pulls up moist air from the Pacific Ocean and Gulf of Mexico, triggering summer thunderstorms.
No matter how much rain a storm brings, it won't erase the ever-present threat of a drought.
Though it's no laughing matter, the punch line to Extension farm management specialist Jim Libbin's favorite weather joke makes the point: What did the New Mexican say on the first dry day after 40 straight days of rain? "We're heading into a drought."
This century, droughts have parched the state in the early 1900s, 1930s, 1950s, 1970s, and 1990s. For New Mexicans who have felt the effects of drought firsthand, it's no comfort to hear that the last 200 years may have been the wettest period in 1,500 years. Researchers with California State University drew that conclusion after examining 2,000 years of tree ring evidence from New Mexico.
Whatever the case, John Fowler, coordinator of NMSU's Range Improvement Task Force, still remembers the best drought advice he heard from an old-timer nearly 20 years ago.
"He told me that unless you're born in the Southwest, you can't ranch here because you don't understand the power of drought," Fowler recalls. "To survive, New Mexico ranchers have to manage as if every year will be a drought. You bet on drought, you use low to moderate stocking rates, and you have financial reserves if you're in it for the long run."
Even after the rains come, it may take years for ranchers to recover financially and to rehabilitate rangeland. In a drought, perennial grasses lose ground to annuals, shrubs encroach, and noxious weeds gain a toehold, Fowler says.
For dryland farmers who try to coax a crop from areas with marginal rainfall, four straight years of dry weather are disastrous. For farmers who must pump water from wells to keep crops alive, energy costs may be prohibitive.
Just as important as how much rain comes is when and how it falls. Averaging covers up many extremes. The first half of the year may be one of the driest ever, only to be followed by record-setting rainfall in the last half. Several inches can fall in a four-hour flash flood or dribble out in quarter-inch showers throughout the month.
Farmers with surface water allotments generally prefer the predictability of scheduling their irrigation.
"Dryland farmers in eastern New Mexico want rain but not hail," Sammis says. "Growers who irrigate don't necessarily want rain. They want control. Vegetable people, like lettuce growers, don't want rain because it can damage their crops."
Though it won't ever set records for total rainfall, New Mexico has the highest number of lightning injuries and fatalities per capita.
The reason is that in wetter climates, rain drives people indoors, where they're protected from lightning, says Hayes, the warning coordination meteorologist.
"What happens here is that people feel a few raindrops, but they don't stop the little league game or the round of golf or the hike along the top of the ridge," he says. "That's why more people get hurt." Dry lightning storms, in which rain evaporates without ever reaching the ground, can start devastating range and forest fires.
Cold snaps: Surviving a roller coaster spring
One way to visualize New Mexico's weather is to slice the state into growing zones based on the number of frost-free days and last frost dates. Divided this way, the state has three diagonal bands that run from southwest to northeast.
The northwest corner has the shortest growing season of fewer than 150 days. A meandering central strip has up to 180 days between frosts, and a southern triangle has more than 180 days.
All of this neat mapping falls apart every spring in the face of notoriously unpredictable cold snaps.
Storms during calving time take a toll on beef cattle herds, particularly if they follow a drought that has weakened animals.
Bad weather also can harm newly imported stocker cattle before they have had time to acclimate.
Deciding when to shear sheep is difficult. "Normally, shearing early carries a bigger risk because of the potential for storms," Parker says. "This year, producers who waited an extra month lost animals because their coats hadn't had a chance to regrow before a late storm hit with 60-mile-per-hour winds."
Roller coaster temperatures damage plants as well.
Tricked by warm days, trees come out of dormancy and start growing, only to be frozen back by a cold snap. "It's so common, it's called Southwest injury," Goldberg says.
Almonds, apricots, cherries, and plums bloom too early to be grown commercially in New Mexico, with its late freezes. "Peaches may have a crop one out of five years," Herrera says. "For apples, it's three to four years out of five, which is the reason they are the only fruit commercially grown in New Mexico."
Cold weather is more welcome in the fall, when it can help defoliate cotton and reduce insect populations. But don't tell that to farmers who planted late or lettuce growers trying to squeeze out a fall crop.
Except for agreeing that they don't like drought and hailstorms, it would be hard to reach a consensus on the perfect weather. The same grower may even want different conditions for each crop.
For farmers and ranchers, the struggle with the elements starts again each season. Given the state's changeable weather, the only safe prediction is that no two years will ever be the same in fair, sunny, windy, stormy New Mexico.