Background Research/Office Work
The search for new caves often begins indoors during a rainy afternoon when there is nothing better to do than look at maps and old descriptions of cave bearing regions. Careful examination of topographic and geologic maps can yield valuable clues in the search a new cave. Most topographic maps have sufficient detail to show blind valleys, intermittant streams, large sinkholes, insurgences, and springs. County scale geologic maps have sufficient detail and are usually accurate enough to guide you into limestone or dolomite bedrock areas. Not all geologic maps are accurate - a lot of the detail on these maps is interpolated. It is usually necessary to field verify the location of geologic contacts and small scale features.
What to look for on topographic maps:
|Blind Valleys/Sinking Streams - Sinking streams or insurgences are dead give-aways that water has formed a cave.
|Sinkholes - Sinkholes or collpsaed areas often indicate karst development in the subsurface. Trends or alignments of sinkholes can indicate the potential trend of cave passages.
|Springs/Resurgences - "What goes down, must come up" is a common phrase in karst terrain areas. Springs are common locations for cave entrances.
This is where the real fun starts. Getting out into the field and actually searching for a cave is one of the most exciting (and sometimes frustrating) parts of caving. Preferably, the field search (i.e. "ridgewalking") should be done on a beautiful sunny winter day when there is no good reason for a sane person to be underground. It can also be a good cure for a nasty hang-over. Puking on the outcrop is much better and more satisfying than puking in the cave.
The best time of the year for ridgewalking is the winter, when there are no leaves on the tress, the undergrowth is the least dense, and when you might be able to detect patches of melted snow, or steam issuing from a cave entrance. Of course, ridgewalking can be done at anytime of the year, but the dead of summer is probably the worst. Most cavers would want to be in the cool underground setting rather than sweating to death, and swatting gnats up on the surface.
A few notes on ridgewalking:
- Check with the landowner to get permission to walk the property;
- Don't ridgewalk alone in remote areas - it's much safer to have a partner;
- Take a map, food and water so you don't have to go back to the car;
- Take a helmet, light, and digging implements in case you find something.
What to look for in the field while ridgewalking:
|Holes, Pits, Voids - uh duh! Areas of obvious blackness and voids leading into the ground could be a cave. No further explanation required.
|Sinkholes or Collapsed Area - shallow or steep depressions in the surface indicate where limestone has eroded and may be connected to a subsurface passage. Many sinkholes are too small to show up on a topographic map. They can only be located and investigated by finding them in the field. Once located, the sinkhole can be inspected for drain holes or other potential leads.
|Limestone Outcrops, Geologic Contacts - Surface expression of limestone bedrock is sign that the soil cover is thin. By following the limestone outcrops, obvious openings or smaller fissures can be easily located. In more mountainous areas, the limestone may form a linear contact with another rock type, and the change in geology is often prone to karst development where surface water has an opportunity to dissolve the limestone and form caves.
|Swallets/Insurgences - If the water disappears into the ground, it must be going somewhere. Look for areas where surface water sinks into a streambed or is diverted into the base of a limestone outcrop. Often, these types of karst features are subtle and required excavation of material to gain access to the underlying cave. Depending on the flow volume and frequency of flooding, the insurgence may be clogged with rocks and debris. Even very small streams may have created a sizable cave passage in the subsurface that leads to a bigger drainage network.
|Springs/Resurgences - If the water is sinking into the ground, it has to come out somewhere - usually in a karst spring. But the pathways are not always obvious, as the route that karst water finds in the subsurface is dictated by the local geology and hydrology. Many karst springs drain water from miles away that may cross surface watershed boundaries. Springs and the areas around springs are good candidates for finding a cave entrance, or a likely site for a dig.
|Dry Watercourses/Wet Weather Streams - In karst terranes, the surface expression of water drainage is sometimes parallel to subsurface drainage. At times of low flow (or no flow) these streambeds will be totally dry, with the water flowing through the subsurface. In times of wet weather, the subsurface conduits cannot carry all the water, the the streambed will carry the water on the surface. In limestone area, these dry watercourses can be good areas to investigate for potential entrances to the subsurface conduits (cave).
|Air Movement - Because of differences in temperature and barometric pressures, most larger caves "breath" in some manner. The flow of air into, or out of, a cave, usually indicates a relatively large volume of space below ground. The breathing effect is cause by the air-filled volume of the cave equalizing with the outside pressure and temperature. A cool breeze issuing from a crack in the summer, or a warm airflow (steam) in the winter is an indication of a fairly large volume of air-filled passage underground. Air movement can also keep the ground around the entrance at a constant temperature, prompting the growth of thick mossy patches.
|Melted Snow - Patches of melted snow can indicate the presence of air movement from a subsurface cavity, as described above. Probing these areas later with a 5-foot piece of rebar may reveal that a root mat is covering a larger void or opening below.
If You Find a Potentially New Cave - What to do next?
|Don't Lose the Location! If possible, document the location using UTM coordinates from a GPS receiver or a topographic map. If a GPS nor a map is available, take bearings to nearby landmarks or simply write down the directions to the cave entrance. It's amazing how cave entrances found in the winter can be lost of difficult to find in the spring or summer. Foliage and/or undergrowth can make it impossible to navigate from memory after the seasons have changed.
|Get Some Help - Don't go alone. Hopefully, it goes without saying that caving is a group activity. Ridge-walking and cave finding can be done relatively safely alone, but the exploration and surveying underground should always be done in a group. Contact a local grotto or the VSS to get some qualified assistance.
|Contact the VSS - See if the cave has been reported previously. If the cave has an obvious entrance, there is a chance the VSS already has a record of the cave. If the cave was dug open or in a remaote area, the cave may be "virgin." With the proper information (UTM coordinates preferably), the VSS can check the database and paper records and tell you if the cave was previously reported.
|File a Report - If the cave has not been previously reported, the VSS would like to know about it and add it to the database. We can can provide a hard copy paper report form, or you can file an electronic report using our online cave report form. You can access the cave report form by clicking HERE.
|Arrange a Survey - If the cave is significant or is threatened in any way, the VSS can contact the right people to conduct a cave survey, check out historical resources, or inventory the natural resources in the cave (biology, etc.). Even if the cave is not significantly large or special, we would still like to add it to the VSS database for future reference.