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Hazards for Visitors

Hazards for Visitors

Touch Me Not! Poison Ivy

A thriving poison ivy patch is a hazard to watch for on the trail. It comes in a small form with leaves the size of your thumb, as well as a deluxe version with leaves bigger than your hand. Most leaves fall somewhere in the middle. On OSMP, unlike other areas, the plant isn't generally reddish, but a dark green shade during summer. The plant has one stem with three leaves off the top. Just remember: "leaves of three, leave it be."


Remember what it looks like and don't touch it! An oil on the plant is what causes the allergic reaction. The oil is easily transferred from fur to skin so don't hug and kiss your dog after s/he's been romping in poison ivy.


Wash yourself and your clothes, shoes and dog in cold soapy water as soon as possible after exposure.

Animals To Be Aware Of

Lions and Tigers and Bears - Oh My!

Learn more on the Black Bears and Mountain Lions page.


Colorado ticks commonly associated with humans are the Rocky Mountain wood tick and the American dog tick. Twenty-eight other species also occur in Colorado. Ticks are blood-feeding parasites that can transmit diseases to humans and other animals.

Avoiding ticks:

Tick habitat includes brushy areas along field and woodland edges and grassy areas. Ticks are most active in spring and early summer.

Bug repellent with DEET (most safely applied to clothing) and pants tucked into socks are your best protection against ticks. Tick checks can be just as effective as repellents because most ticks take several hours to settle in and begin feeding.

Removing a tick:

Barbed mouth parts may remain imbedded causing an infection after the tick is removed. Fortunately, the Rocky Mountain wood tick has fairly short mouth parts and is easily removed. Using blunt tweezers, grasp the tick as close to the skin as possible. If you must use your fingers, grasp the tick through a tissue or thin piece of plastic to avoid the possible transmission of any diseases. Pull slowly and steadily, straight away from the skin taking care not to crush the tick if possible. Disinfect the site and wash your hands when finished. Ineffective methods include covering them with petroleum jelly or touching them with a hot match.

Bees & Wasps

Bees will buzz and sting if you swat at them. Generally they don't mistake people for flowers and will not do much more than double check your omnivorous nature before moving on to a better source of pollen. They are extremely important pollinators, responsible for the reproduction of the beautiful wildflowers you enjoy in the meadows and forests, so please let them bee...


The western black widow spider, Latrodectus hesperus , the famous shiny black spider with the red hour glass on her belly, is the only poisonous spider found in Boulder County. They are actually very shy and prefer to avoid all contact with humans. It is our responsibility to anticipate their presence in favorite spots like woodpiles (and abandoned rodent holes) and behave with appropriate caution.

If you are bitten the area will probably become red, and you may or may not feel the bite. The venom is a neurotoxin which induces severe muscle cramping and spasms. The large muscles of the legs and abdomen usually cramp first and the pain is very acute. Some people also experience anxiety, nausea, profuse sweating or increased blood pressure. In severe cases paralysis, convulsions and stupor can occur. Small children and elderly people are the most vulnerable to death, but this rarely occurs.


Transport to a hospital as soon as possible where intravenous muscle relaxants can be used to stop the cramping. Antivenin is used in severe cases where muscle relaxants have no effect.

Other worrisome spiders: You will hear that the brown recluse spider is also found here. Not true. This spider’s bite results in necrotic skin lesions. Much misdiagnosing happens in hospitals, where without the spider in hand, infected bites from other creatures (such as ticks, fleas, bedbugs, mites and assassin bugs) are incorrectly attributed to the brown recluse. The spider's most distinguishing features are the 6 (not 8!) eyes arranged in pairs on the head and an abdomen without color patterns. For more information on recognizing the brown recluse visit Richard Vetter's University of California, Entomology website.


Of all the species of snakes living in OSMP, only the Prairie Rattlesnake is venomous. It has a look-a-like in the bull snake. The rattler has a more wedge-shaped head than the bull snake, but they both have a similar brown splotched pattern. The rattler has a more distinct frame of white and black around each block of brown. And of course only the rattler has the famous musical rattling tail, and only the rattler is poisonous. The twist is that the bull snake will mimic the rattler's behavior, coiling and shaking its tail back and forth, making a rattling noise against the dry vegetation when available, if you get too close.

Prevention of bites: Snakes are not inherently aggressive. They bite to defend themselves when feeling threatened. Simply keep your distance and observe them in safety. Remember that they are cold-blooded (exothermic) and seek sunny warm places in the mornings and evenings. Hiking only on designated trails reduces your risk of meeting a rattlesnake, and also helps you "Leave No Trace" on Open Space and Mountain Parks.


Stay calm. Often you won't know for sure if the snake was venomous. It's always safest to assume that it was and follow these precautions: keep the bitten area below your heart and have someone get you help rather than walking out yourself to keep your pulse and circulation down, slowing the venom's movement to your heart. If rescue is not far away, sit tight. Let them come get you. If you are out in the back country, there are a few more things you can do. Wash the bite with soap and water, because infection is a high risk complicating factor to snake bites. If you have a snakebite kit, use the suction device to remove venom.

DO NOT cut the bite area or use your mouth to try to extract the venom. That adds greatly to the infection potential.

West Nile Virus

Learn the facts about West Nile Virus, how you can prevent contracting West Nile Virus and the City of Boulder's West Nile Virus Management Plan on the Mosquito Control Program page.

Weather In the Rocky Mountains

Lightning Can Kill You!

So just what do you do if you're caught outdoors in a thunderstorm? First things first PAY ATTENTION. Watch the sky for dark, towering clouds, notice the wind. These are warnings that weather is brewing. When you can hear thunder you are 10 miles or less from the storm. The distance traveled between one strike and the next can be as much as 6-8 miles, so it could reach you quickly. Count the number of seconds between the lightning and the next thunder clap, divide by five and that's how many miles away from you the lightning hit. If the count was 5 seconds, that lightning was only a mile away!

Avoiding lightning

Thunder and lightning occurring simultaneously. If your hair stands on end, lightning is about to strike very near you!

  • DO NOT be the tallest thing around, and DO NOT be under the tallest thing around. Get off the mountain.
  • Move out of open, exposed areas, and away from water and ALL metal. Move into a clump of shrubs or trees of uniform height.
  • Crouch or kneel with your hands over your ears to protect your hearing from the thunder.
  • Spread your group out while maintaining visual contact. Lightning can spread 60 feet across the ground from the strike point.
  • DO NOT put your hands on the ground.
  • DO NOT lay down on the ground. That provides a path for the electricity to run right through your heart!

First Aid treatment for the strike victim

Do not become another victim! If the victim is in an area at risk for another strike you must decide when and how to get to them or whether you should move them to a safer place. Remember, you cannot help if you become incapacitated. If the victim has not fallen or been thrown by the lightning, there are rarely major injuries that would prevent safely moving the victim. A person who has been struck by lightning doesn't hold an electrical charge and can't shock another person. Check if the victim is breathing and has a pulse. If not, perform CPR if you know how to and send someone for help. If you are alone, give CPR and call for help. Survival chances are greatly increased if you administer CPR immediately. If the victim is burned—most likely where the lightning entered and exited the body—provide first aid as necessary.

For more information on lightning visit the National Weather Service Lightning Safety page.

Hypothermia - Staying Warm In Summer Rain Storms

Hypothermia in the summer time?
You bet!

Summertime rain can be an everyday experience, so plan accordingly. At this altitude, the rain is cold and your body temperature can drop rapidly. Pay attention to the weather forecast and bring extra layers.

Signs and Symptoms

Hypothermia results in muscular and cerebral impairment. Stumbling, mumbling, fumbling and grumbling are indicators of changes in motor coordination and levels of consciousness. 


Conserve body heat by putting on additional layers of dry clothing. Wear wool, polypropylene or fleece, which provide insulation when wet. Cotton or down have no insulation value when wet. Eat carbohydrates for quick energy, proteins and fats for the longer run, and drink plenty of water. Move around to generate more body heat. Warm liquids or foods, additional exercise, heat from a fire or friend who is warm will all help. Get help before the condition becomes severe.

If the situation does become severe, a hypothermia wrap is the best way to re-warm someone when additional food, drink and exercise are not helping. Make sure they are in dry clothes, ideally polypropylene, insulated from the ground and wrapped in as many layers as possible, aiming for 4 inches of insulation all the way around. "Space" blankets are helpful (and easily portable in a day pack) and plastic wrapped around the outside is important.

Sun, Friend or Foe?

Overexposure to sunlight, elevated body temperatures and decreased fluid levels on hot days can result in heat disorders such as sunburn, heat exhaustion, heatstroke and heat cramps. Normally the body cools itself by sweating. Fluids and salts (which help maintain circulation and brain function) lost through sweating can be replaced by eating lightly salted foods and drinking beverages such as Gatorade, frequently and in small amounts. If you plan on visiting the Rocky Mountains, please prepare yourself for the heat and sunshine. Drink plenty of fluids before, during and after your visit.


Ultraviolet light from the sun is very intense in the Rocky Mountains due to the high altitude. Sunscreen, hats and sunglasses are critical to prevent damage to the skin and eyes.

Heat Cramps

Heat cramps are severe muscle spasms caused by excessive sweating and salt (electrolyte) loss during exercise on a hot day.

Heat Exhaustion

Heat exhaustion occurs when there is excessive fluid loss due to sweating. Symptoms include heavy sweating, fatigue, weakness, dizziness and cold, pale and clammy skin, increased pulse and respiration, normal to slightly elevated temperature, possible fainting, vomiting, confusion and anxiety. Heat exhaustion can lead to heat stroke, a light threatening condition, if not treated properly. To treat, lie down in a cool place; apply wet, cool cloths to the victim's skin. Replace fluids and salt slowly.

Heat Stroke

This is a life-threatening condition. It occurs when a person can't sweat enough to lower their body temperature. Immediate intensive treatment is required; rescue must be initiated. The key symptom of heat stroke is hot skin. Onset of heatstroke can be very rapid. To treat while awaiting rescue, move the patient to a cool spot or shade them yourself. Loosen or remove clothing and pour water on their limbs while fanning them to increase evaporation. Massage the limbs to help the cooled blood on the surface of the body get back to the heart more quickly.

Ice on ponds and lakes

You can help to keep you and your pets safe by keeping them off OSMP's icy lakes. 

Many times, pets that fall into icy waters will be able to get out or self-rescue without assistance.

If it happens to you while visiting OSMP and your pet is unable to get out of the water, stay off the ice! Call 911 and Boulder Fire-Rescue will respond and rescue your pet! 

High Altitude Effects

"High Altitude" is considered land above 5,280 feet. The Mesa Trail and all points west are above this altitude, so watch for effects, particularly if you or your guests are from out of town and lower elevations. Symptoms include: nausea, shortness of breath, restlessness, insomnia and diarrhea. As you are exercising you may experience: rapid heart rate, headache, nasal congestion, coughing and easy fatigue. If you experience symptoms while hiking, turn around, go back down and rest. If symptoms persist, call a doctor or emergency room for guidance.