Using Satellite Images

Before visiting a lake you’ve never skated on before, it can be useful to search for recent satellite images of the lake. Satellites pass over New England every few days, and if the skies are cloud-free, crystal-clear images can be obtained.
As of April 2024, the best images can be found on the Sentinel Hub EO Browser by following these steps:
1. Go to this link to see New Hampshire’s Lakes Region: https://apps.sentinel-hub.com/eo-browser/?zoom=11&lat=43.62663&lng=-71.58417
If this isn’t your area of interest, pan and zoom to the correct area.
2. In the screenshot on the upper right, note that satellite Sentinel-2 is selected by default, with a blue check mark next to it. This satellite usually provides the highest-quality images, so don’t change the selection. Toward the bottom left of the screen, you’ll see a large green button labeled ‘Search’ . Click it.
3. A list of satellite image ‘thumbnails’ will be displayed on the left side of your screen. Select the most recent cloud-free image and click ‘Visualize’.
4. Click ‘False color’ to view an enhanced image that increases the contrast between land and water, snow and ice, and even differentiates between black ice and gray ice.
5. You’ll see an image like the one in the lower right. Practice identifying the following types of features:
a. DARK RED - Forested land
b. SOLID WHITE - Snow-covered fields (or snow-covered ice)
c. LIGHT BLUE - Gray ice (Lighter shades of blue are weak snow ice with a high air content; darker shades of blue are solid dark gray ice with fewer air bubbles)
d. DARK GRAY - older black ice (may be crisscrossed by thin blue lines, which represent healed cracks of pressure ridges)
e. SOLID BLACK - open water or new black ice (it is impossible to distinguish them in a satellite image, so on-site inspection is required)

Above: Initial view showing a choice of satellite data sources. (Click ‘Search’)
Below left: Thumbnails of images from the past month. (Click ‘Visualize’)
Below right: Selection of enhanced color schemes. (Click ‘False color’)

Below: False-color image of northern Lake Winnipesaukee from early February 2024, showing gray ice in light blue, black ice in gray, and open water in black.