After leaving Jackson Hole on our way to Bozeman, MT, to visit Randall's cousin Jim, we had the amazing opportunity of driving through two of America's most magnificent National Parks – Grand Teton and Yellowstone. I had never been to Grand Teton before so I was particularly excited about spending time in that park. We were treated to perfect weather with just a few puffy white clouds in the deep blue sky, and with Randall's Interagency Senior Pass, we saved $50 in park entrance fees so it was a good day before we even entered the Visitor Center.

Given that we were only passing through the parks, we made just a brief stop at the Grand Teton Visitor Center. We then hopped out and in of the car at viewpoints along the Teton Park Road, overlooking Jenny Lake, and at the top of Signal Mountain Road. Throughout we had incredible views of the jagged peaks and deep canyons of the Teton Range.



One of the Grand Teton peaks over Jenny Lake

Rising precipitously from the sagebrush dominated floor of the Jackson Hole Valley at an elevation of 6,320 feet (1,926 m), the highest point in the Teton Range is the granite summit of Grand Teton (13,770 feet or 4,197 m). The absence of foothills makes the view of the looming mountains particularly spectacular from the valley's flat floor. The 2.7-billion-year old rocks at the core of the range are some of the oldest in North America but the mountains are some of the youngest in the world, having started to form just 10 million years ago. This is when movement along the Teton fault generated massive earthquakes which caused the mountains on one side to rise while the valley floor, on the other side of the fault, dropped.

This vertical displacement reached almost 30,000 feet before erosion by wind, rain, ice, and glaciers started to reduce the difference. Starting 2 million years ago, massive glaciers up to 3,500 feet (1,067 m) thick periodically flowed south from Yellowstone. As these ice sheets filled the valley, alpine glaciers carved the jagged Teton skyline and deposited moraines of debris that eventually made the dams for the beautiful lakes along the base of the Teton Range. A few of these tiny alpine glaciers remain, of which the most obvious one is Teton Glacier, just below the highest peak. However, with climate change these have receded by 15 to 25 percent in the last 40 years.



The Grand Canyon of the Yellowstone River

Leaving the Grand Teton Park, we passed through the John D. Rockefeller, Jr. Memorial Parkway on our way to Yellowstone. When Rockefeller visited Jackson Hole in 1920, he was dismayed by the haphazard development marring the landscape. To protect the Teton scenery, Rockefeller began buying land in the Jackson Hole Valley, more than 32,000 acres (13,000 ha) of which he donated to the federal government. Grand Teton National Park was established in 1929. Yellowstone was the first of the US National Parks to be protected, having been signed into law by President Ulysses S. Grant in 1872. There are now 59 National Parks distributed across 27 states and the territories of American Samoa and the US Virgin Islands.



Steaming vent near Old Faithful in Yellowstone National Park

Rather than lying on a fault line like Grand Teton, much of Yellowstone lies within a 30- by 45-mile volcanic caldera (48 by 72 km). Huge volcanic eruptions had occurred in the area 2 million, 1.3 million, and 640,000 years ago, of which the last ejected 240 cubic miles of debris (that's quite a bit). The magmatic heat that had powered these eruptions is responsible for the park's geysers, hot springs, fumaroles, and mudpots. We visited the site of Old Faithful, but learning that it would be another hour before it was next expected to erupt and having seen it erupt on previous visits, we watched another geyser and then headed towards the dramatic vistas of the Grand Canyon of the Yellowstone River. We had seen mudpots and the Mammoth hot springs calcium carbonate terraces on previous visits so we enjoyed the drive north of the Grand Canyon without many stops.



Waterfall in the Grand Canyon of the Yellowstone River

Through the parks, we saw not only elk, but also pronghorn antelope, mule deer, and bison. Our visits to these parks might have been rushed but in just one day we were privileged to see some of the most spectacular scenery and some of the more impressive wildlife that North America has to offer.



Eroded pillar-formations along the Yellowstone River north of its Grand Canyon