FOP Leader Handbook

Weather

We must run the safest trips possible in order to achieve any of the other goals of the program. You, as the leader in the field, ensure the success of the program by using sound judgment, and by not hesitating to opt for the safer and more conservative course of action. Prevention is important both as an attitude and an approach towards risk management. Thoughtful prevention techniques can help to minimize dangerous situations. In the case of weather, anticipation is the key to prevention. Anticipating the weather will enable you to make better decisions in terms of crossing ridges, planning days, and choosing routes. Constantly and vigilantly monitor the weather, the sky, and the clouds. Even the tiniest changes can signal major changes in the weather.

Foul weather in the city can be enough to depress our spirits, but conditions are rarely dangerous. However, in the back country, the weather is of much greater importance; a slight rain may greatly increase your chances of hypothermia and a wind that would go unnoticed in the city is enough to make a lake dangerous for paddling. When you are distant from sources of help, weather conditions can profoundly affect the group’s safety. Anticipating the weather conditions so that appropriate accommodations can be made is therefore highly important - what good is a raincoat over an already wet FOPper? Be prepared to deal with varying weather conditions. Wearing layers, staying well-hydrated and fed, and monitoring the group are essential steps.

Predominant Weather Patterns of New England

In general, weather conditions come from the same direction, which in New England is from West to East. However, in this area storm patterns often come from the South or North. Storms come more often from the South, but are generally more severe when they come from the North. So, a look to the West will tell you what major weather patterns are due, but check to the South and North as they can be the sources of more dangerous and fast moving systems.

How Weather Changes

Poor weather is a result of hot and cold air from different systems meeting. Air from different systems meets when a low-pressure area forms. Where atmospheric pressure is low, air from surrounding areas moves in to equalize the pressure. Cold air from lower in the atmosphere rushes in to meet the hot air already present. The meeting of cold and hot air causes precipitation and wind. Thus, low pressure is a sign of poor weather on the way.

Signs of Low Pressure

Because low pressure is a sign of poor weather, we can also anticipate an incoming storm by observing the following signs of dropping pressure:

• Birds flying very low or even not at all. Birds are very sensitive to changes in pressure. If you observe birds flying low in trees, making a lot of noise, or don’t even notice birds at all, that is a sign of dropping pressure.
• The usually unseen and much paler bottoms of leaves will be visible when wind (and often weather) comes from a source other than usual. The change causes leaves in trees to be blown in unusual directions. If you can see the bottoms of leaves on trees as the wind gusts, that means it is coming from a different direction than usual and could be bringing a storm.
• Insects are highly sensitive to changes in pressure as well. If the bugs that had been bothering you are no longer present, it is likely a sign of dropping pressure.
• Outhouses can be good signs of dropping pressure as well. When pressure drops, the higher pressure inside the outhouse created by the heat of decomposition will make the air in the outhouse flow out and all around the campsite. Outhouses always smell bad, but if you can smell the outhouse from far away it is a sign of dropping pressure.
• If your ears pop while you are hiking, it could be a sign of dropping pressure. It could also signal numerous other things, but to be safe, if your ears pop while hiking take a look at the weather to see if other signs of dropping pressure are present.

Clouds

Although more accurate prediction of the weather requires equipment that just doesn’t fit in a backpack, short-term forecasts can be made through careful observation. Clouds are the best indicator of approaching weather and they should be monitored frequently, even if only briefly. Look to the West to see what clouds are approaching, and also to the South and North, as they are often the source of bad storms. Things to look for:

• High, wispy clouds (cirrus clouds): Seen at altitudes greater than 6,000 m (20,000 ft). Precipitation in 24 hours. Cirrus clouds serve as a warning of an approaching system that may bring rain; often these clouds are only seen as a halo around either the sun or the moon. Frail tufts of white are a sign of fair weather and should not be mistaken for the foreboding cirrus. If you see these clouds, start thinking about how weather might affect your route and, if necessary, what alternatives are available.
• Middle level clouds (altostratus and altocumulus clouds): Seen at altitudes be- tween 2,000 and 6,000 m (7,000-20,000 ft). Precipitation in 6 hours. These clouds are reasonable indicators of rain, especially when preceded by cirrus. These middle-level clouds can be gray in color and cover the entire sky (creating a typical bleak New England day). As the fluffy cumulus and veil-like sheets of stratus clouds descend, precipitation is imminent.
• Fluffy, changing clouds (cumulus clouds): Fair weather. Cumulus clouds are puffy and do not cover the sky; they are irregular in shape and size (which is why you love to guess what animals, etc. they are). Do take note, however stationary cumulus clouds over a mountain range can indicate late afternoon thunderstorms. These clouds should be watched carefully if they begin to show vertical development, as they can produce a lot of rain.
• Towering, dark, triangular clouds (cumulonimbus clouds): Thunderstorms likely (treat very seriously). These extensive clouds can extend from low levels (~2000 m) to heights over 7 kilometers. Cumulonimbus clouds are very tall, dark, and triangular. They are often shaped like an anvil, with the top part trailing far behind the bottom part across the sky. Be aware that other cloud layers can obscure the characteristic triangular top. These formations should be watched very closely, especially when your route calls for travel above tree-line.
• Cloud cap over mountain peaks: can indicate cold and windy conditions on the peak.
• Lens-shaped light clouds (lenticular clouds): deteriorating weather. These lens-shaped clouds usually form on the sides of prominent peaks and are very obvious to the eye.

Rain

Keeping everyone warm and safe is essential in the outdoors. Be prepared to deal with changing weather conditions, and always be prepared for rain.

• Since it can’t be avoided, think protection. Maintaining a dry set of clothes is essential. Also, when hiking, both you and your FOPpers should always have raingear accessible so that you can stay dry in case of sudden rain.
• Waterproof clothing and sleeping bags by putting them in garbage bags. Bring several extra garbage bags in case one gets ripped.

Wind

Wind, especially when combined with rain, can have strong effects on a person’s body temperature. When it is windy, your body loses heat through convection (5.5); people have been known to get hypothermia on 60-degree days due to wind. Always be aware of the amount of wind and avoid unnecessary exposure to windy conditions.

• Remember to take into account wind-chill factor, as even a light breeze can significantly lower the temperature. Windy days are tiring because of the excess demands on your body to maintain its temperature.
• Wear raingear. It provides added insulation by blocking the wind and preventing some of the body heat from escaping.
• Choose protected campsites, and be aware that dead standing trees or trees with shallow root systems can be blown over in strong winds.
• Staying hydrated is also important; because sweat is evaporating it may not feel like you are losing as much water as you are. Be aware of fluid loss.

Lightning

Lightning generally occurs during thunderstorms, when warm air rises and creates ice crystals which collide and release electrons. This forms a difference in potential which causes the electrons from the ground to branch towards the ground. A lightning strike causes air to rapidly expand, creating a sound wave known as thunder. In calm air, thunder can be heard up to ten miles from its lightning strike; in turbulent air, thunder can be heard only for about five miles and this number is significantly reduced in heavy rain or severe winds. The delay between the lightning strike and the thunderclap can be used to estimate your distance from the strike for every five seconds between the strike and the thunder, the lightning is one mile away (10 seconds = 2 miles).

Understanding where lightning is likely to strike often depends on terrain. Lightning is likely to strike where there is water or metal, as both are excellent conductors. Additionally, since a lightning strike occurs whenever a stepped leader from the cloud meets a streamer from the ground, the closer the streamer is to the stepped leader, the more likely it is to create a channel for lightning. Thus, streamers from high points such as trees and mountaintops are most likely to result in lightning.

It is important to remember that the electrical effects of lightning are not limited to the strike zone, but instead extend to a broad area surrounding it as the electrical current dissipates.

The Risks of Lightning

Direct strikes are the most potentially harmful risk associated with lightning. In a direct strike, a stepped leader extending from a thundercloud meets a streamer rising from a person’s body, and up to 30,000 amps of electricity flow through or over the body to the ground in a matter of milliseconds. Because the human body is mostly water, it is a good conductor of electricity. In a situation where the body is higher than or as high as other objects in the area, the risks of a direct strike are high.

Indirect current can affect the body in myriad ways and can vary from minimally risky to equally risky as a direct strike. The first way a person can be indirectly affected by the current of a lightning strike is through streamer currents. Streamer currents are not the primary channel through with the electrons of a lightning strike flow, but the lesser current of a streamer current can still be strong enough to cause serious injury or death. Streamer currents can also affect a number of individuals simultaneously if they are positioned within 20 feet of each other. Avoid becoming a conduit for streamer currents by taking the same precautions as for avoiding direct strikes.

The second way a person can be indirectly affected by the current of a lightning strike is through ground current. Ground current is the flow of electricity over the ground just following a direct strike, and it is the cause of approximately half of injuries associated with lightning. Avoiding areas such as mountaintops, areas with tall trees and water will help to avoid being in the proximity of a direct strike and, therefore, the risk of being affected by ground current. Sitting or crouching on an insulating pad provides almost negligible protection from ground current (the high voltage of lightning can jump the distance between the ground and a person’s body), as does crouching or sitting with feet together, which may help reduce the amount of current flowing through the body. Despite this, the standard procedure in the outdoor industry is to use the lightning position in rare high-risk situations because it is less risky than standing or moving in such situations.

The third way a person can be indirectly affected by the current of a lightning strike is through unsafe protection in shelters and exposed tarps. Any building or shelter that is not completely enclosed is unsafe in the event of a lightning strike because the opening on the side of such a shelter forces the lightning to jump the gap, which creates the potential for indirect flow through persons inside the shelter. The highest danger area is near the opening of a shelter. Additionally, wet ropes are excellent conductors of electricity, and if a tarp is somewhat exposed in a rainstorm where lightning is present, the strike may occur at the ridge-line and jump to the people underneath, as they are excellent conductors as well.

Hypothermia is associated with lightning situations because if only reactive strategies are deployed, people may be forced to sit or stand still in inclement weather for ex- tended periods of time. Any strategy that seeks to manage the risks of lightning must also seek to manage the risks of hypothermia that are almost always present when lightning occurs.

Managing the Risks of Lightning

The first strategy for managing the risks associated with lightning is to anticipate a high-risk situation and move to a low-risk location. It cannot be stressed enough the decreased risks associated with being positioned in low, gently rolling terrain, away from water and where water might flow, surrounded by reasonably uniform cover, in comparison to needing to assume the lightning position in an exposed or high-risk location. The lightning position is not a safe alternative to being in a low-risk location. Low-risk locations are not risk-free lightning can strike in such terrain, but streamers cannot form and, thus, direct strikes are random and infrequent. If the group is in a low-risk location whether under tarps or not the lightning position is not man- dated, but can be used as a tool if deemed necessary.

If a storm has arisen so quickly that a low-risk location cannot be safely sought, the lightning position should be used. The lightning position is not safe; it is the best option in a high-risk situation, but should not be considered a comparable alternative to being in a low-risk location. To assume the lightning position, each member of the group spreads out at least 30 feet from each other in a circle or triangle formation so that lines of communication remain open. Each person squats with feet together or kneels with knees and feet together on a pack or other insulating material. The aim of the lightning position is to get bodies low (so as to reduce the potential of a direct strike or streamer current) and to reduce the points of contact with the ground (to reduce the risk of ground current flowing through or over the body). If a group finds themselves under tarps or in a shelter in a high-risk situation, leaders must be particularly aware of both the hypothermia risk associated with assuming the lightning position and the threat to group safety if two leaders are struck simultaneously because they are not separated.

Deaths from lightning have occurred when individuals were upright and seeking safer terrain; no one in lightning position has been struck. Nonetheless, the lightning position is not a safe alternative to proactively anticipating the risks of lightning and responding by seeking out safer terrain where lightning is significantly less likely to strike.

Furthermore, seeking protection in shelters or exposed huts is associated with the high risk of a strike occurring if the shelter is exposed and a high risk of indirect current when the lightning jumps the opening. An exposed tarp with a wet ridge-line presents a similar risk of indirect current. All metal (including internal frame back- packs) must be avoided in high-risk situations when the lightning position is being used. Remember that in high-risk situations, leaders must stay separated to avoid the risk of both being affected simultaneously.

Using Good Judgment in Matters of Lightning

Consider:

• Risk of direct strike
• Risk of indirect current, including for open shelters - Risk of hypothermia

Prioritize:

• The immediate threat
• The most serious threat
• Seeking out a low-risk location (low, rolling terrain; away from water or where water might flow; relatively uniform ground-cover that is reasonably taller than humans)
• Getting into lightning position if seeking a low-risk location is not possible

Thermoregulation and Equipment/Layering

Below is an explanation of the process by which we produce and lose heat. You should keep these processes in mind when making sure everyone has appropriate gear. Also, you may want to give your FOPpers a brief overview of what thermo- regulation is so they understand the importance of hydration, layers, and food in the backcountry.

How Thermoregulation Works

When we are in the woods, as opposed to Cambridge, there is no escape from the weather. Thus, we have to rely on our own bodies and the materials in our pack to regulate our body temperature. To do this we must first understand where heat comes from and where it goes.

Sources of heat production:

• Metabolism: the process of burning glucose in your body that occurs constantly
• Digestion/nutrition: turning food into usable energy
• Exercise/shivering
• External sources of heat: fire, other people, sun, etc.

Sources of heat loss:

• Evaporation: heat from our body is transferred to water as it changes into a gas. Fluids of any kind, whether sweat, rain, or water from a nearby stream, can cause heat loss through evaporation.
• Radiation: infrared energy given off by warm objects (i.e. us). Any hot object will radiate heat to its colder surroundings.
• Convection: heat transfers from a solid object to air (heat is actually carried off the body vs. passive radiation). The faster the air is moving and the more air that is in contact with the human body, the more heat will be carried away from the body. Wind is an important consideration for convection.
• Conduction: heat transfers from one solid object directly to another solid object. Conduction is an important consideration in encouraging the use of ensolite pads to stay warm. Direct contact with the cold ground will remove heat from your body quickly.

How to Stay Warm in Cold Conditions

Prevention is essential. Monitor each other, make sure individuals are wearing the proper attire, and keep the group warm. Many individuals don’t like to admit that they are cold, and judgment is affected early in the onset of exposure.

Know your equipment and how to use it. You should also help your FOPpers pack and make sure their equipment is suitable. Through prevention and proper use of equipment, you can stay warm.

• Internally: Drink and eat a lot. Food and water help your body to create energy and keep you warm. Make sure that everyone is eating and staying hydrated.
• Externally: Proper layering will help ward off cold by reducing the amount of heat you lose to the environment. A good layering system will allow you to get the most out of your clothes. Also, don’t forget to keep your head and other extremities warm with hats and gloves

Layering system:

1. Wicking layer: This layer of synthetic undergarments wicks water away from your skin before evaporation can take place, keeping you warm. The reason cotton is bad in cold conditions is the same reason it is good in hot ones: it keeps moisture close to your body, allowing for evaporation that keeps you cool or dampness that can make you cold.
2. Insulation layer: This layer is essential for warmth. Sweaters and heavy shirts made of pile, synchilla, and wool create a thick pocket of warm air next to your body, limiting heat loss due to radiation. Again cotton is not preferred, but better than nothing.
3. Wind/rain layer: This layer must be absolutely waterproof! Rain gear doubles as wind gear. This layer prevents convection heat loss by blocking the wind from the warm insulation layer. It also prevents rain from soaking your insulation and wicking layers.

What to do in case of cold:

• Put on warm clothing and keep the extremities warm, especially the head.
• Go to the bathroom. Your body wastes energy heating up the urine in your bladder to keep it warm.
• Give food and liquids. Hot drinks can warm an individual up quickly.
• Watch for the initial signs of hypothermia (apathy, listlessness, loss of fine motor skills, uncontrollable shivering, denial of cold while obviously under- dressed) and take protective action at onset of symptoms. Don’t wait for an emergency to develop before stopping to warm up. Emergencies should absolutely be prevented.
• Do not share sleeping bags. This practice is outdated and dangerous (be- cause it puts another person at unnecessary risk). One can, however, pre-warm a sleeping bag or use a hot water bottle wrapped in a sock.
• Exercise is another way to keep your body warm.
• See also section on hypothermia (Part VII, Wilderness First Aid)

How to Stay Cool in Hot Conditions

Making sure you are cool on a hot day can prevent injuries and will improve the feeling of your group. Again, monitor the group, making sure individuals are drinking enough and wearing protective clothing. Be careful of pushing the group too hard or without frequent water breaks, as many individuals don’t like to admit when they are tired or thirsty in a group environment.

• Internally: Drink water! Water and snacks will replenish the fluids and electrolytes that your body loses through sweat.
• Externally:
  • Avoid sunburn, sunstroke and heat exhaustion by taking early protective action. Keep pants and long-sleeved shirts within easy access and wear a hat.
  • Sunglasses prevent headaches resulting from the sun’s glare on water and protect eyes from burn damage.
  • Protect skin from harmful UV rays with sunscreen; lead by example and put on more sunscreen than you need to. Your FOPpers will take their cues from you.

What do to in case of overheating:

• Rest in a cool shady area.
• Drink plenty of water and grab some snacks.
• Fan the person.
• Place a cool washcloth on his or her forehead or gently splash water on the skin to speed up the cooling process.
• Be wary of heat exhaustion and heat stroke.