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Flooding Issues Frequently Asked Questions

at Onondaga Cave State Park

Please note: It is nearly impossible for the park staff to warn campers of an impending "flash" flood. Conditions necessary for flash flooding to occur are random and based on previous weather events, ground saturation and recent rainfall trends. As a result, campers are encouraged to monitor weather patterns before and during their trip. Local news casts and/or internet weather sites ( or are good sources for weather information. Park personnel will make every attempt to inform campers during check-in if heavy rains are expected during their campground stay. Unfortunately, they may not make contact with every person, so please take the initiative to be adequately informed of any weather situation that might affect your stay. If we have not come to you, seek out the campground host and ask for an update.

What conditions cause the campground to flash flood?

The campground creek does indeed flash flood; however, this is not something that occurs very often. Regardless, campers should be prepared for changing weather conditions. If heavy rains are expected, park staff will make every effort to inform campers during check-in. This does not guarantee that every camper will be reached (nor does it guarantee that the campground creek will flood), so please attempt to keep yourself apprised of the situation.

What should we do if the campground creek flash floods?

If conditions deteriorate, campers should pick up small items and place them on the picnic tables or in vehicles to keep them from floating away. Typically, the creek only flash floods about 6-12 inches over the ground, but this occurs very rapidly. It also usually happens overnight when most campers are sleeping. Therefore, if it is raining hard when you retire for the evening, assume the possibility and put your small items up and out of the way. Should you awake to or find yourself in a flash flood situation, please do not attempt to leave the campground. STAY PUT! No national safety organization will tell you to try to drive through flash flooding or cross swollen creeks. The flooding itself will be gone as fast as it comes up. Also, it is never powerful enough to harm vehicles or campers. It will, however, affect tents. Tent campers should plan accordingly.

How do we get in and out of the campground if the entrance road floods?

Generally, the most common issue with flooding involves only the entrance to the campground. The water will backup in that area for one to three days depending on the amount of rain received and the river flood stage at the time. The campground itself remains unaffected. To access the campground, you will need to use the park's secondary entrance. That road is marked with signage when the entrance floods and generally there are "water over road" signs placed in the roadway leading to the normal entrance. In addition, during normal business hours, you can inquire at the visitor center for directions to the campground. If you are in the campground when the entrance floods, you will leave by the secondary entrance; there is a gate located to the left of Blue Heron Trail that will be open and accessible to campers in the event that park staff must ask you to leave. ONLY major flooding of the Meramec River would prompt park staff to do so.

What are the different flood stages for this campground?

"Flood stage" for this area is 12 feet. This means the river must rise to 12 feet before it will begin to come out of its banks. During most normal weather conditions, it is at or below 3 feet. Therefore, it takes more than one day of heavy rain or several days of multiple inch rains for it to do so. This stage will affect only the "entrance road" as stated above.

"Moderate flood stage" for this area is about 20 feet. This affects the basic loop of the campground, the basic sites on the other side of the road and briefly the secondary entrance in and out of the campground. There have been RV campers staying in the campground during stages close to this with no ill effects. Worst case scenario is they stay at their camper for a day or two or drive through the water at the secondary entrance as it only gets between 6 and 12 inches over the road. The campground hosts are there as well. However, staying at this point if the weather forecast is calling for additional rainfall is discouraged.

"Major flood stage" for this area is 25 feet. Once the flood stage goes beyond 20 feet, campers are not allowed in or out of the campground. There is a tertiary exit from the campground via the park's special-use area road that would be utilized in case of an emergency evacuation. Historically, the Meramec River goes into major flood stage here about once every 10 years. However, this doesn't mean that it cannot occur more often. The last major flood prior to the spring of 2008 was in July of 1998.

Will the reservation system contact us if the campground is flooded?

It is possible that they may contact you concerning flooding but will likely only attempt to do so if your reservation must be canceled due to flooding. When flooding of the entrance gate or campground might affect your reservation, park staff contacts the reservation system via email prior to noon on Thursday before the weekend to arm them with the most current information regarding your stay. The best way to find out if there is an issue is to visit the park's webpage. Any alerts will be posted at the top of this page. This information can be accessed 24 hours a day and is regularly updated. There are only postings if there is a potential problem. However, your best option is to pay attention to the weather prior to your visit and be prepared.

Will we be refunded for our camping stay should flooding occur?

Typically, your camping night will be refunded should flooding disrupt your stay and you have to leave or are asked to leave. Storms, heavy rain or use of the secondary entrance do not constitute a refund. Power outages of more than six hours associated with a storm do constitute a refund. Should an event constituting a refund occur, speak with your campground host.

What should I do in case of a storm or high winds in the campground?

The best place to go in the event of a storm or high winds is the showerhouse. If you have light items such as lawn chairs, you should secure them and stow your awnings. High winds can wreck havoc on your camper awnings. The trees are not your friend during a storm or high winds. They can blow over or limbs can drop out of them. DO NOT stand under them. The Division of State Parks is generally not liable for storm damage to your vehicle or camper as these events are beyond their control. Should a limb or debris damage your property, please speak with a park staff member who will assist you in filling out a damage report for your insurance company.

What should I do in case of a tornado?

Should a tornado warning occur during regular business hours, park staff will instruct you to come to the visitor center and enter the cave. If this occurs during off hours, go to the showerhouse breezeway and stay there or seek the lowest possible area, lie down and cover your head.