Airplanes serve as the primary means of transporting people, food, supplies and essential services across Alaska’s remote and challenging landscapes. Photo: Steve Betts, Flickr (CC).
Alaska, often called the Last Frontier, is defined as much by its breathtaking beauty as by the demands of daily life in an untamed and challenging environment. Spanning 425 million acres, its immense scale and rugged terrain leave about 85% of the state’s 740,000 residents without access to a major road network, which makes aviation and maritime transportation essential for food, medical care and other necessities. These realities shape daily life, where resilience and innovation support everyday survival.
That resilience is continually tested by Alaska’s many environmental hazards. Communities regularly contend with heavy precipitation, river-ice jams, glacial lake outbursts, flooding, avalanches, debris flows, wildfires, volcanic activity and coastal storms, all of which pose serious risk to lives, property and livelihoods. Compounding these challenges, Alaska’s high latitude increases exposure to space weather, which can disrupt communications and navigation systems.
A glacial outburst, in which water dammed by a glacier suddenly gives way and releases downstream, led to historic flooding and severe damage to residential areas in Juneau, Alaska, in early August 2024. The Mendenhall River gauge reached 15.99 feet on the morning of August 6, surpassing the previous year’s record of 14.97 feet. Photo: Alaska National Guard, Flickr (CC).
Of the many LEO instruments used by Alaskans, the JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) stands out for its versatility. VIIRS collects global visible and infrared observations of Earth’s land, atmosphere and oceans, supporting critical applications that protect life and property and enhance the nation’s economy.
In Alaska, forecasters, pilots, mariners, natural resource managers, emergency managers and other decision-makers use VIIRS imagery to monitor clouds and fog, weather systems, river and sea ice, snow cover, fire and smoke, volcanic emissions, flooding, vegetation health, ocean color, freezing sea spray and even city lights at night to track power outages.
Left: Operational JPSS satellites—NOAA-21, NOAA-20 and the NOAA/NASA Suomi National Polar-orbiting Partnership (not shown)—circle the Earth from pole to pole in low Earth orbit, providing complete global coverage twice each day.
Right: The NOAA National Weather Service (NWS) operates seven land-based Next-generation Radar (NEXRAD) stations in Alaska, using high-resolution S-band Doppler technology to monitor weather. Credit: NOAA.
Of the many LEO instruments used by Alaskans, the JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) stands out for its versatility. VIIRS collects global visible and infrared observations of Earth’s land, atmosphere and oceans, supporting critical applications that protect life and property and enhance the nation’s economy.
In Alaska, forecasters, pilots, mariners, natural resource managers, emergency managers and other decision-makers use VIIRS imagery to monitor clouds and fog, weather systems, river and sea ice, snow cover, fire and smoke, volcanic emissions, flooding, vegetation health, ocean color, freezing sea spray and even city lights at night to track power outages.
Alaskan fire managers have long relied on VIIRS observations to quickly detect and monitor wildfires, track smoke plumes and estimate fire temperature and intensity. This information guides critical decisions, including evacuations and allocation of resources such as aerial support. VIIRS fire products also support prescribed burns by providing site-specific data that verify ground-based observations, promoting safe and effective fire management across Alaska’s vast and varied forests.
The VIIRS Day Land Cloud Fire RGB product shows the lightning-caused Tatlawiksuk Fire in Southwest Alaska in June 2022, overlaid with heat points (red, orange and yellow dots) derived from the VIIRS Active Fire (VAF) algorithm, which express the fire’s intensity in megawatts (MW). The reddish hues are the fire and freshly burned ground, and a large blue-gray smoke plume extends southwest. The VAF algorithm is also a key input to the NOAA operational High-Resolution Rapid Refresh (HRRR)-Smoke model, a real-time weather model that predicts the movement and concentration of smoke from wildfires across North America. Image: Geographic Information Network of Alaska (GINA)/University of Alaska.
One of VIIRS’s most valuable contributions in Alaska emerges at night, when the lack of visible light limits weather observations. During Alaska’s long winter, some regions experience weeks with little or no daylight, increasing forecasters’ reliance on infrared imagery. In infrared observations, however, clouds are difficult to distinguish from snow and ice because their similar temperatures make them appear equally bright white.
VIIRS’s unique Day/Night Band (DNB) addresses this limitation. The DNB is highly sensitive to low levels of visible light at night, enabling the detection of reflected moonlight from clouds, snow and ice during Alaska’s extended dark periods.
The VIIRS Snow/Cloud Discriminator (VSCD) uses the DNB along with other VIIRS bands to produce color-coded imagery that clearly separates clouds from snow and ice. These around-the-clock observations support critical applications such as tracking low clouds and ice motion to improve safety for maritime navigation in Alaska’s ice-covered waters.
The critical LEO observations that support Alaskans are explored in greater depth in Feature 1 of the 2025 LEO Science Digest, Resilience in the Last Frontier: The Role of LEO Observations in Alaska. Released each January, the Digest highlights innovations and real-world applications of LEO satellite data, showing how these observations enhance weather forecasting, improve environmental monitoring, support disaster response and benefit the nation’s economy.