Old Faithful Bounces Back?



To analyze regrowth and recovery after a major forest fire.


  • Time series of Landsat images of Yellowstone National Park


In the spring of 1988, lightning sparked the first of what we now call the Yellowstone Fires. But it wasn't until November--half a year later-- that heavy snow smothered the last smoldering ember. 

Yellowstone National Park - August 2, 1989

Yellowstone National Park (outlined in white) - One year after the fires.
Image Processing by Janet Chien

From spring through summer and into the fall, thousands of firefighters battled the blazes, and millions of gallons of water and chemicals were dropped on the Yellowstone flames. Before it was over, more than 800,000 acres of the Park were burned. (Another 600,000 acres of forest outside the Park were also destroyed.) The color red on the Landsat image above shows the location of fire damage both within, and adjacent to the Park.

Now that it's been over ten years since the fires, signs of recovery are clearly visible. Burned areas appear pink on the 1999 image (eleven years after the fires).


On July 27, 1988, the Yellowstone Fires threatened to burn Old Faithful Lodge, but the wind shifted and the fire turned south. The grand old lodge was saved, but there was great destruction of forest in the Old Faithful Geyser area. Trees, bushes, and undergrowth of all kinds were destroyed in this, the most popular area of Yellowstone National Park.

The Superintendent of the Park has just been awarded a grant from the National Park Service. The money is to be used to study the recovery of forests after a fire. Two sites near Old Faithful Geyser will be selected. Both sites must have been severely burned, one of them must be recovering rapidly while the other must be recovering slowly.

A team of scientists will study the two sites in detail. The scientists will try to determine what factors contribute to a rapid recovery in one case, and a slow recovery in the other case. Your job, working together with the rest of your class, is to select the two best sites for the team to study.

The links below will take you to Landsat data that show the Old Faithful area before the fires, soon after the fires, and approximately 11 years after. (Click here to learn how to interpret the data.) Your teacher will assign each student in your class one of 36 small areas to evaluate. You will click on your area to see three enlarged views for comparison. The questions your class is trying to answer are:

  1. Which of the 36 small areas shows the most recovery? and,

  2. Which shows the least recovery?

  3. How do you determine recovery rates from the satellite data?

Before you start, explore the images and try to decide how you will rank the different areas. How can you compile and display the class data? How will you select the "winners"?


July 1986

August 1989

July 1999

Click here to see a topographical map of the Old Faithful area.

To see Landsat images of the entire Yellowstone National Park region on these dates, click on these links (the park is outlined in white):

Before the fires.

One year after the fires.

Eleven years after the fires.

Chick here to see Landsat images of the Old Faithful area of Yellowstone National Park on these dates. On those images, the Old Faithful pointer only points in the general direction of the Old Faithful Geyser. Can you find the exact Old Faithful site on each image?


Tomorrow, the Superintendent needs your answer. What two areas will the scientists study?

Prepare a memo to the Superintendent of Yellowstone National Park in which you name the two areas you have selected. (You may use the letter and number that identify the areas you have chosen.) Explain your selection by explaining how each area meets these requirements:

  • the sites must have been severely burned

  • one must be recovering

  • the other is either not recovering at all or is recovering very slowly

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