Is Montana at Risk?
Identified Hazards for the State of Montana
Basic Disaster Information:
DROUGHT and EXTREME HEAT
Drought must be defined not only in terms of below normal precipitation, but also in terms of duration. Occasional periods of below average precipitation will not seriously deplete moisture reserves, while prolonged shortages of moisture can be enough of a drain on moisture reserves to seriously affect crops, livestock, forest and range lands, as well as hydro-electric, irrigation, and urban water supplies.
The effects of drought become apparent with a longer duration because more and more moisture-related activities are affected. Non-irrigated croplands are most susceptible to moisture shortages. Rangeland and irrigated agricultural lands do not feel the effects as quickly as the non-irrigated, cultivated acreage, but their yields can also be greatly reduced due to drought. Reductions in yields due to moisture shortages are often aggravated by wind induced soil erosion.
In periods of severe drought, forest and range fires can destroy the economic potential of the timber and livestock industries, and wildlife habitat in, and adjacent to, the fire areas. Under extreme drought conditions, lakes, reservoirs, and rivers can be subject to severe water shortages which greatly restrict the use of their water supplies. An additional hazard resulting from drought conditions is insect infestation.
The Palmer Drought Severity Index (PDSI), first developed in 1965, is a means of quantifying drought in terms of moisture demands versus moisture supply. Moisture demands include plant requirements and water needed for recharge of soil moisture supplies. An allowance is also included for runoff amounts necessary for recharging both ground water and surface water supplies such as rivers, lakes, aquifers and reservoirs. The PDSI balances the moisture demands against the moisture supply available.
The PDSI expresses this comparison of moisture demand to moisture supply on a numerical scale that usually ranges form positive six to negative six. Positive values reflect excess moisture supplies while negative values indicate moisture demands in excess of supplies.
The 1930's Dust Bowl remains the most highly publicized of past droughts in Montana, but may not necessarily be the worst or the last to be seen by our state.
The mid 1950's saw Montana with a period of reduced rainfall in eastern and central portions of the state. In July of 1956, four counties applied for federal disaster aid due to greatly reduced precipitation amounts since June of the previous year. By November of 1956, a total of 20 Montana counties had applied for federal drought assistance. Montana found itself in another drought episode in 1961. By the end of June, 17 counties had requested designation as federal disaster areas due to lack of moisture, higher than normal temperatures, and grasshopper infestation. Small grain crops died before maturing, and range grass and dryland hay crops were deteriorating rapidly. Livestock water supplies were at critical levels. In July of 1961, the State’s Crop and Livestock Reporting Service called it the worst drought since the 1930's. Better conservation practices such as strip cropping were helping to lessen the impacts of the worst water shortages since the 1934-36 years.
By August of 1961, 24 counties had applied for federal drought disaster aid. Five years later in 1966, the entire state was experiencing yet another episode of drought. Although water shortages were not as great as in 1961, a study of ten weather recording stations across Montana showed all had recorded below normal precipitation amounts for a ten month period. By August of 1966, the Bitterrott Valley was experiencing its worst drought in 25 years, and the state arranged to sell water to local irrigators.
A seven month survey ending in May of 1977, estimated that over 250,000 acres of Montana farmland had been damaged by winds. Inadequate crop cover and excessive tillage practices had resulted in exaggerated soil damage due to inadequate soil moisture supplies. This drought episode was most severe in the western and southcentral parts of the state.
Water supplies were so critical by June of 1977 that officials from Montana were working with others from Idaho, Washington, and Oregon on the Northwest Utility Coordination Committee in an attempt to moderate potential hydroelectricity shortages. On June 23, Governor Judge issued an energy supply alert and ordered a mandatory ten percent reduction in electricity use by state and local governments.
Eastern Montana found itself with another well-established drought episode in 1980. The southeast corner of the state had received less than four inches of precipitation since July of 1979. In the northeast corner of the state, Glasgow received only 4.74 inches in the period from June of 1979 to May of 1980, making it the first twelve month period on record since 1905. Grasshopper infestations were seen in isolated areas, little wheat was planted, and large numbers of livestock were being sold due to the hay and water shortages.
By October, estimates of 1980 federal disaster payments were five times those paid in 1979. In Richland County alone, 600 of the county’s 800 farmers had applied for federal payments. Total drought related economic losses from Montana in 1980 were estimated to be $380 million.
The drought that had started in 1979 continued into 1981. March snowpacks were at 50-60 percent of normal, initiating forecasts of critical water shortages later in the season. All areas east of a north-south line running from Havre through Billings had received less than their normal precipitation in the first three months of 1981. Wolf Point had received only six inches since June of 1979. Fortunately, large May storms brought moisture to much of the state, but then flooding started to occur in the formerly parched areas. The northeast corner of the state, where forty percent of Montana’s wheat crop is produced, remained the driest area of the state, despite the spring storms.
Inadequate moisture supplies were again the problem in 1984. By July, many of the Hi-Line cities were experiencing water shortages and rationing schedules were put into effect. Conrad businesses voluntarily closed to help curtail water use. The seven districts involved in the Milk River Irrigation Project were out of water, and crop losses were estimated at $12 - $15 million. August of 1984 saw Montana in flames with numerous forest and range fires burning out of control.
Drought continued to plague the state in 1985. All 56 counties received disaster declarations fro drought during this year. April estimates by the Montana Crop and Livestock Reporting Service put the state’s pasture and range at 65 percent of normal, while conditions in the northeast corner of the state were down to 32 percent of normal. From 1982 through 1985 cattle herds were reduced by approximately one-third.
The continued lack of moisture in 1985 resulted in a wheat crop which was the smallest in 45 years. Grain farmers received more in Government deficiency payments and insurance money than they did for their crops. For a typical 2500 acre Montana farm/ranch, the operator lost more than $100,000 in equity over the course of that year. The state’s agriculture industry lost nearly $3 billion in equity.
The extended effects of this drought included the loss of thousands of off-farm jobs, the closing of many implement dealerships and Production Credit Associations. The mild winter of 1998 has presented us with another potentially dry year. With below normal precipitation in many parts of the state, several counties have applied for assistance.
Droughts are most often predicted only after they are well-established. The National Weather Service issues seasonal forecasts for expected precipitation amounts, but these long-term forecasts are somewhat limited in their accuracy and should not be taken as the final work on next season’s drought conditions. They can serve as warning signals to be aware of other drought warning signs that can be watched and used as guidelines in water-related management programs.
Analyzing the causes of drought is another means considered in predicting recurrence. Long-term weather pattern, such as droughts, are the result of complex global weather patterns. Due to this complexity, climatologists and meteorologists still do not agree on exactly what causes drought. Part of the complexity has to do with the long-term cycles involved in shaping the global weather picture. Smaller cycles are often superimposed over longer term cycles which make the global picture even more unclear.
With the realization that drought is an inevitable part of life in Montana, the important issue is, what to do to lessen its effects. Since it is a difficult phenomenon to predict ahead of time, the best approach to mitigation is implementation of water conservation practices.
As mentioned earlier in the historical summary of Montana’s droughts, agricultural practices have improved through the years so that the adverse effects of severe moisture shortages have been reduced somewhat. Because soil moisture is an important moisture reserve, soil conservation programs are also water conservation programs. Leaving stubble as a mulch on fields in the fall catches and holds more moisture in the forms of snow, and also keeps soild from being blown away. Strip cropping helps to reduce wind erosion during the growing season while providing a more efficient use of soil moisture than straight fallow in areas prone to saline seep. Planting shelter belts also serves as a menas to reduce erosion.
In connection with the PDSI, calculations can be made to determine the amount of precipitation needed to bring the moisture balance to near normal. These figures are available during the growing season, along with the bi-monthly PDSI, in the UDSA’s Weekly Weather and Crop Bulletin. These figures could be useful in determining if a drought episode is severe enough to make planting of non-irrigated grains impractical. If the precipitation deficits are beyond reasonable seasonal amounts, chances are good that small grains planted would not provide economic yields. Depending upon the severity of the moisture shortage, grain varieties not usually planted in years of good precipitation due to their relatively low yields, might be considered because of their ability to maintain adequate yields under low moisture conditions. If moisture deficits are beyond reasonable expectations, below normal yields could be expected from non-irrigated hay acres, and reductions in livestock herds could be considered. Such examples of management decisions associated with soil moisture reserves in Montana are numerous.
In good moisture years, it is difficult for farmers and ranchers to see the benefits of conservation practices because soil moisture is not always an asset reported on economic statements. A public information program about the drought hazard in Montana is the best way to ensure good water management in the agricultural sector.
Wise forest management is also important in mitigating the effects of drought. Thoughtful lumbering practices will ensure an adequate supply of trees on the slopes to catch and hold the snowpack through the critical seasons. Revegetation of logged areas is important for the same reasons. Management in these watershed areas directly affects the amount and quality of water that enters into Montana’s rivers and streams, and subseequently its lakes and reservoirs.
Once the water is into the rivers, lakes and reserviors, its conservation becomes the responsibility fo those drawing from those reserves. Water conservation at the residential, commercial, municipal and industrial levels should focus on management fo both supply and demand. Supply management programs may consist of metering, leak detection and repair, pressure reduction, watershed management and evaporation suppressoin. Demand management programs may include pricing, regulation and education. You can only be expected to manage wisely if you are well-informed about the resource.
Drought is a special type of disaster because its occurrence does not require evacuation of an area nor does it constitute an immediate threat to life or property. People are not suddenly rendered homeless or without food and clothing. The basic effect of a drought is economic hardship, but it does, in the end, resemble other types fo disasters in that victims can be deprived of their livelihoods and communities can suffer economic decline.
At least 50 percent of the state’s electricity comes from hydroelectric generators. Over one million acres under irrigation are harvested each year. Dryland farming and ranching continue to contribute a large percentage to the state’s agricultural production. Forestry supports a significant segment fo the population. Recreation not only brings in out-of-state dollars, but is a very important part of life to Montanans as well. All of these functions require adequate supplies of water.
Meteorologists and climatologists have established that droughts are a natural part of the global climatic cycle, and that it is not unusual for them to be severe and prolonged in semi-arid areas like Montana. Their severity can be aggravated by the improper use and management of water and related resources duch as soils and forests. People using these resources in Montana must have adequate information available to them in order to make wise management decisions.
A drought is an extended period fo unusually dry weather. Droughts become severe if several months pass without significant precipitation. Extreme heat is defined as temperatures that are ten ro more degrees above the average high temperature, and that last for several weeks during the hottest time of the year. Drought and extreme heat can cause shortages of water and food crops. Parched lands are more susceptible to wildfires during periods of drought. Droughts can actually result in later flooding. The vegetation dies without water, and as a result, even average rain can cause flooding.
