Droughts are difficult to define, as they are dependent on the region one is occurring in. For Anchorage, a drought might be classified differently than say, Las Vegas, where there is very little rainfall over the course of the year, or even Seattle, which receives a substantial amount of rainfall over the course of a year.
According to the National Drought Mitigation Center, a “drought is an insidious hazard of nature. It is often referred to as a “creeping phenomenon” and its impacts vary from region to region. In the most general sense, drought originates from a deficiency of precipitation over an extended period of time–usually a season or more–resulting in a water shortage for some activity, group, or environmental sector. Its impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought.”
Because of the fact that there are different types, and different reasons for a drought, lets first look at the types: Meteorological/ Climatological, Hydrological, Agricultural, and Socioeconomic.
A Meteorological Drought is an unusually long period where precipitation is below average for a particular area. The chart below shows the average high and low temperatures for each month in Anchorage, as well as the precipitation levels per month.
According to U.S. Climate Data, the average annual amount of rainfall in the city is 16.57 inches over the course of an average 103 rain days per year. To go along with this, the average annual snowfall is recorded as 74 inches. Anything substantially below this could be considered a meteorological drought.
This refers to an unusual deficiency of ground water and/or stream flow. Based on the information we found at USGS, the water levels seemed normal for the current conditions, however, the website was a little too confusing to figure out historical data.
This is a period of deficient moisture in the soil layers from which crops and other plants normally draw their water.
According to Drought Reporter, this year was a record year for wildfires in Alaska. This was reported as the whole state, not just Anchorage, however, it is still useful to note. Also in the state, beef, butter, corn, olive oil, and almond prices are at record prices, whereas, there also is a water conservation alert out. These all contribute to explaining how an agricultural drought is affecting Alaska.
A Socioeconomic Drought occurs when the moisture shortage is sufficiently large enough to impact people. This can be expressed through changing prices/demands on economic goods and even actual water shortages.
Same as in the agricultural drought, with crops obviously at a low, this means that the demand is higher, creating a need to raise prices. This agricultural drought has an impact on the economy, making prices higher and causing financial issues in the state.
There are different ways of deciphering whether or not a drought is occurring at the time. In class we have discussed the Palmer Drought Severity Index, the Crop Moisture Index, and the Drought Monitor. All of these are important in helping figure out whether or not a drought is occurring, as well as how severe the drought is at a given time.
Palmer Drought Severity Index
This index measures precipitation deficiency with respect to local climate condition and is based on departures from normal for a location, providing a relative measure that can be compared across regions. The reading is cumulative, meaning that it is difficult to change with one or two weather events.
Crop Moisture Index
This index is a shorter-term index, varying week to week, which measures the soil moisture in the crop-rooting zone.
The US Drought Monitor
The U.S. Drought Monitor, established in 1999, is a weekly map of drought conditions that is produced jointly by the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture, and the National Drought Mitigation Center (NDMC) at the University of Nebraska-Lincoln.
The U.S. Drought Monitor, a composite index that includes many indicators, is the drought map that policymakers and media use in discussions of drought and in allocating drought relief.
There are a few causes of droughts, which can be helpful to us, however, even with knowing what can cause a drought, or how to identify a drought, “all signs fail in times of drought.” This can make it very difficult to accurately predict a drought, however, spring and summer are often the key seasons for droughts to develop.
Droughts are associated with significant departures from normal weather patterns, while we can look to upper-air charts to find patterns in the upper level waves, Jetstream, and subtropical high-pressure systems.
There is an abnormally dry “drought” currently occurring in the region of Alaska. This has increased food prices, as well as wildfires in the area. The cause of this has been the lack of significant rainfall, as well as less snowfall during the winter months. Adding to the drought has been the cause of a heat wave, or warmer temperatures for over a year. Because of all these factors, less water is available for the state to combat the abnormally dry effects occurring in the region.
Droughts can be significant damaging to cities or regions due to failure of farms and crops, less water for daily activities that need it, and due to the effect it can have on people. Droughts can lead to a dust storm or heat waves, which in and of themselves can cause medical problems, as well as death. Due to droughts, we can see higher increases in the costs of oil, gas, food, or supplies. This does not help when economically prices go up, as it can strain a whole region of money and resources.
Sources are hyperlinked, however, here are more sources we gained information from: