Evacuation Time by Terrain Calculator

Enter your route info into the calculator (above). Once you do, the app will calculate distance for you. Saving you a guesswork step (and saving all of us from a rush).

But it doesn’t stop there; the calculator goes beyond simply the straight-line distance on your map, to the distance beneath your feet. One mile across a paved road isn’t equal to one mile along a snowy ridgeline or through brush. The calculator add these terrain factors to slow the theoretical pace to real-world conditions. You’ll go fast on a paved surface, but thick brush or soft sand may halves your pace.

How to Plan Your Evacuation Route Safely

The most important factor is who else is joining. A common mistake is people thinking about how long they think they can go and assuming everyone else will be at that same pace. Big mistake. You need to use the pace of the slowest member of your party as a basis for your guess. Traveling with kids, elderly parents, injured friends, those all adds huge amounts of time. The calculator uses group pace factors to include those delays in overall speed. It makes you admit that traveling with others slows you down more than just going alone… something crucial when evacuating safely.

Momentum is reduced by load: Carrying a light daypack lets you keep moving steadily; cramming an emergency bag full of gear will slow you down. You must slows down every time you carry that heavy pack. The tool adjusts your starting speed based off the load factor you choose.

It is the same with visibility. Traversing a well-marked trail during daylight is no problem, while walking in darkness or smoke means constantly checking the route. All those halts adds up fast. Add in the non-walking time. When you hear an order come in, there’s always some lag time from then until you’re out the door. It can eat up an hour before you even start moving. With the calculator, you can add in that fixed delay to your travel time.

Next comes the planning buffer. That’s the last percentage that covers things you just don’t know. On a nice clear summer day, maybe a five percent buffer will suffice. In volatile conditions, a buffer of twenty-five percent or more is wise. This puts out the total time it will take and how much extra margin you have over your cutoff time frame. It also tells you how far apart checkpoints should be. This allows everyone to know when to hit key points so that morale stays up and no one gets lost.

If the estimated time isn’t within your safety window or daylight hours, then there is no way to walk this route. Plan B may include other means of transportation or being stuck in one spot. It all depends on terrain. Rocky trails require paying close attention with each step. Mud sucks at your boots. Snow requires careful foot placement and lots of breaks to warm hands and feet. You’ll be moving at least as slow as shown in the reference tables (on this page) when on rough terrain versus flat paved surface. Use these to check the sense of your input. For instance, if you select a rugged off-trail route and then choose a fast pace, you’re not going to add up.

The point of evacuation planning is to manage uncertainty. The weather/behavior of the fire isn’t up to you to control but your expectations are. Run the numbers ahead of time so that there’s no guessing when it matters most (i.e., during the panic). What does ‘I need to get this far within one hour’ look like? Under stress? Will there be a bunch of people around you also going? How fast will I move? And then plan to match that. A measured departure instead of a chaotic scramble.

Begin at the most difficult conditions. Assume the heaviest load and the poorest visibility. If it doesn’t work there, it won’t work if it is easier. It isn’t about speed. It’s about being out. Once, calculate. Often, verify. Always add in some margin for error. Your safety depends on knowing exactly where you stand before you ever take a step. Your life depends upon it.