The question of whether Alaska is a desert requires a precise understanding of climate science. The answer is overwhelmingly no, though there are important regional qualifications. Alaska’s vast landscape features a wide spectrum of climates, from temperate rainforests to polar conditions, placing it far outside the definition of a desert. The misconception that its cold, snowy environment qualifies as a desert confuses low temperatures with a lack of precipitation. To address this, one must first establish the scientific criteria for aridity.
The Scientific Definition of a Desert
A desert is fundamentally defined by its lack of moisture, a condition known as aridity, not by its temperature. The accepted benchmark for an arid environment is an area that receives less than 10 inches (approximately 250 millimeters) of annual precipitation. This low total can be in the form of rain, snow, or fog, making precipitation the most important factor for classification. This definition applies equally to hot deserts, such as the Sahara, and cold deserts, like Antarctica.
The distinction between these types is based on temperature, but the defining feature remains the moisture deficit. Cold deserts exist in high latitudes or at high altitudes where low temperatures limit the available moisture. The aridity threshold is sometimes refined using the Köppen climate classification, which compares precipitation to potential evapotranspiration. Conversely, a cold region, where evaporation is low, can be considered arid even with slightly higher precipitation totals.
Alaska’s Dominant Climate Zones and Precipitation Levels
The majority of Alaska is too wet to be classified as a desert, primarily due to the influence of the Pacific Ocean. The state is dominated by three main climate zones: the maritime coast, the continental interior, and the arctic zone. Coastal regions, particularly Southeast Alaska and the Gulf of Alaska coast, have a maritime climate with exceptionally high precipitation. These areas host temperate rainforests, with the southeastern panhandle receiving annual precipitation totals exceeding 200 inches.
Populated areas like Anchorage, which has a subarctic climate, receive far more moisture than the desert threshold. Anchorage averages 15 to 20 inches of annual precipitation, well above the 10-inch desert limit. Juneau, the capital, is significantly wetter, recording nearly 67 inches annually. These high totals result from moist air masses moving inland from the Pacific Ocean, where they are forced upward by coastal mountain ranges, causing heavy rain and snowfall.
Alaska’s Arid Exceptions
Despite the state’s overall wet character, certain localized regions exhibit precipitation levels that fall below the desert threshold, creating arid exceptions. The most notable example is the Arctic Slope (North Slope), which stretches along the Arctic Ocean coast. This area has an arctic climate and experiences extremely low precipitation, often receiving less than six inches of annual moisture.
This aridity is due to cold temperatures, which cause the air to hold very little water vapor. The Brooks Mountain Range also creates a powerful rain shadow effect, blocking moisture-laden storms from the south. Even with precipitation totals as low as four inches in places like Utqiaġvik, the area is usually classified as a polar desert or a cold semi-arid steppe rather than a true desert. The presence of permafrost and low evaporation rates means the limited moisture that falls is retained, preventing the ecosystem from behaving like a hot desert with similar precipitation levels. These arid areas are localized exceptions that do not define the climate of Alaska as a whole.