On this EarthCache, you will learn about the history of the area, take temperature measurements contribute to our understanding of the hot spring system, and document an ever-changing rock formation. This information will help the park learn how the hot springs temperature changes over time, how they compare to other hot springs in the park, and it will give you a unique look at one of the many amazing natural features at Mount Rainier National Park.
Important: Stay on the trail at all times and do not drink the water.
OHANAPECOSH: HOT SPRINGS BY GOSH!
The hot springs at Ohanapecosh (pronounced oh-HAN'-uh-puh-kahsh) have a long history, highlighting how land management has changed at Mount Rainier National Park. The springs provide a great opportunity to learn about geology and biology.
The oldest features you will encounter on this Earth Cache are the rocks of the Ohanapecosh Formation. The Ohanapecosh Formation contains the oldest exposed rocks in Mount Rainier National Park, and is between 40 and 20 million years old. The rocks formed during thousands of eruptions of volcanic ash, lava flows and mudflows, both on land and under the sea. At Mount Rainier National Park, the Ohanapecosh Formation is between 9,000 and 15,000 feet thick!
More recently, the volcano we know as Mount Rainier started erupting 500,000 years ago. With each new eruption, lava would pour out, cool, and turn to rock, building the mountain higher and bigger. Today, the mountain we see is the result of hundreds of eruptions that built it up, and the tireless sculpting of glaciers and landslides tearing it down.
Although you are standing on the skirt of a volcano here at Ohanapecosh, it is not the heat from the volcano that warms these springs. Instead, the springs form from water moving so deep below earth’s surface that it becomes hot and quickly flows back up to the surface along faults and cracks. While the water is flowing through the ground, it is dissolving minerals and gas, which cannot escape until the water reaches the surface. While you are walking the Nature Trail you will see what happens when the dissolved minerals and gas reach the surface.
When Mount Rainier National Park was created in 1899, the park boundary did not include the Ohanapecosh area or the hot springs. It was not until 1932 when the park boundary was moved east to the Cascade Crest, and far enough south to include the Ohanapecosh area that the hot springs became part of Mount Rainier National Park.
The earliest effort to protect this area came in 1893 when the Pacific Forest Reserve was set aside, primarily designed to protect the area from logging. The Pacific Forest Reserve eventually became the Mount Rainier Forest Reserve in 1897. It has since been divided into Mount Rainier National Park and the Mount Baker-Snoqualmie, Wenatchee and Gifford Pinchot National Forests.
Before 1932 when the springs were still outside the park boundary, the hot springs were progressively developed into a large health resort. Eva O’Neal opened a tent camp in 1912 that attracted many early vacationers to the hot springs, and in 1921 N.D. Towers secured a permit to build a hotel and bathhouses at the Ohanapecosh Hot Springs. By 1924 Towers and his associate Dr. A.W. Bridge had built a hotel and two bathhouses. Bridge became the sole owner of the resort two years later, and continued to operate and expand the hot springs until 1947 when the resort was sold to Martin Kilian. At the resort’s height, there were 32 cabins, a large bathhouse, a five car garage and several maintenance buildings. Kilian ran the resort until 1960 when the park service decided to end the concession contract and began restoring the area to its natural condition, removing the bathing pools and buildings. Today, the hot springs are still being restored, and in order to preserve them for this and future generations, please enjoy them from the trail.
Today, elk are the main users of the hot springs. They visit the area year round, but in winter when the heat from the springs melts snow-free spots, the elk find warmth, nutrient-rich water and lots of fresh green plants to eat. The animal tracks and scats you can see are a reminder that this water is not good for humans to drink!
Another group of animals can be found at the hot springs, but unless you brought a microscope along, you will have a hard time seeing them! Tiny algae that can photosynthesize call the Ohanapecosh Hot Springs home, and we call these tiny algae diatoms. There are at least 26 species of diatoms in the Ohanapecosh Hot Springs, and together with the diatoms in the world’s oceans, they produce a large part of the oxygen in our atmosphere. Thank them when you take your next breath of fresh air.
As part of this Earth Cache, you will be taking and recording temperature measurements. There are calibrated stem thermometers available for you to use at the Ohanapecosh Visitor Center (open late May through early October - call 360-569-6046 for up-to-date hours of operation). Even if you have your own thermometer, we would prefer that you use the provided stem thermometers to help us get the most accurate information about the hot springs. In addition to using good consistent instruments, HOW you use them is even more important. To make sure everyone measures the temperature of the hot springs in the same way, you will follow a “Standard Protocol”, just as scientists do when performing lab work and research in the field!
Standard Protocol for Measuring Temperature:
At each of the waypoints/locations, follow these steps to measure the temperature.
Remember to stay on trail and watch your step while measuring.
Hold the thermometer by the end with the metal loop and pocket clip or by the attached string. At the specified waypoint location, place the end of the thermometer that has holes in the metal casing into the water so that all the holes are fully submerged, but no further.
Leave the thermometer submerged in the water for 60 seconds. This will allow the thermometer to fully adjust to the new temperature. Especially when the water is hot, it will take some time for the thermometer to change and reflect the correct temperature.
While the thermometer is still in the water, locate the red line on the thermometer, and find the highest point where it crosses the numbered black lines. The lines are numbered in 20 degree Fahrenheit increments, and each black line between the numbered lines represents a change of 2 degrees Fahrenheit. Record the temperature to the nearest degree (eg. 81 degrees F).
To claim this Earth Cache online at geocaching.com, you must do two things:
1. Walk the Hot Springs Nature Trail and take temperature measurements (following the Standard Protocol!) at four designated locations with the provided thermometer. Head back to the visitor center, record your temperature measurements in the log book (see the example in the log book) and return the thermometer.
2. Take a photo, and/or provide a detailed description of Waypoint #5, the Travertine Mound. Include how it looks, if there is steam or algae present, where the water is flowing, etc., and post the photo/description at geocaching.com.
Waypoints for the Hot Springs Nature Trail:
1. Ohanapecosh Visitor Center (N 46° 44.156’ W 121° 33.977’)
Built in 1964 as part of the Park Service’s Mission 66 improvements, this visitor center is only a few years away from becoming eligible as a historic landmark. Ask at the desk for the Earth Cache box, and you will find these instructions printed out, as well as a log book and a stem thermometer that you can borrow for this Earth Cache. You can pick up a trail map for the area that includes the Hot Springs Nature Trail, as well as some other great trails in the area. The Hot Springs Nature Trail begins just to the right of the impressive “tree cookie” out the back door of the visitor center.
2. Tributary Creek to the Ohanapecosh River (N 46° 44.156’ W 121° 33.941’)
The first stop you will make is just a few feet down trail, at the marked junction for the Nature Trail. There will be a footbridge on your left that crosses a small stream. This stream is one of the many tributaries to the Ohanapecosh river, and is a great place to see an example of the cool, clear snowmelt water that feeds the Ohanapecosh. Take your first temperature reading here on the bridge (remember to use the Standard Protocol). After taking the temperature, walk the Nature Trail counter-clockwise, heading right from the bridge.
3. Orange Spring (N 46° 44.149’ W 121° 33.887’)
The next stop is at the first hot spring you come to on the trail! It is located just past the wooden post with the number five on it. This small seep has an interesting color to it, and though many people guess the color comes from rust, the orange shade is thanks to the algae that grow in the warm water. While standing on the footbridge across the stream, take the temperature and see how it compares to the chilling streams of the area.
4. Above the Old Plunging Pools (N 46° 44.249’ W 121° 33.750’)
As you continue on the trail, you will arrive at a large network of hot springs seeping out of the ground. If you are out on a cool day, there may be steam rising from the pools of hot water. Look to your right as you cross the wooden footbridge and you will see bubbles coming out of the springs. The location for you to take the temperature measurement is a little further down the trail, between sign post 16 and 17. On your left there will be a particularly warm spring coming out from under a rock. Where the trail meets the spring on the left, take your third measurement. Just below your measurement spot are the remnants of the old plunging pools used during the resort days. Keep walking down the trail and when you come to the next trail junction, head left back towards the campground.
5. The Travertine Mound (N 46° 44.246’ W 121° 33.792’)
The last hot spring feature you see on the trail is this impressive rock formation, best seen from the wooden footbridge through the grass and sedge meadow. As the springs emerge from the ground in ever-changing locations, the minerals dissolved in the water drop out, forming a rock called travertine (a form of calcium carbonate). The rocks here are constantly changing and growing, and in some places the deposits are 25 feet thick. Take your last temperature measurement where the water meets the wooden foot bridge, and also take a photo or make a detailed description of the travertine mound (include things such as how it looks, where the water is flowing, the color of the algae, and anything else you notice).
2016 was the 100th anniversary of the National Park Service, and to celebrate, Visit Rainier and the Washington State Geocaching Association (WSGA) hosted the Visit Rainier Centennial GeoTour - 100 caches placed in and around Mount Rainier National Park. The geocaches highlighted the rich history, scenic wonders, quaint communities, and hidden gems of the Rainier region. The caches were released in four series of 25 caches each during 2015 and 2016.