Track and intercept tornado mechanic

I like the theme of your game idea.

Like you mentioned you could always use a grid system and roll die but the trick is if you have an area where a tornado is more likely to spawn how to weight it so a tornado would appear there more often but not 100% of the time so there is some uncertainty. Maybe take the center point of the high risk area and use a die roll to determine if the tornado will form north or south of that point (indicated by a positive or negative sign) and by how many spaces. Another die roll would determine if the tornado forms east or west of the center point by the same method.

My friend made a similar game back when Twister first came out. He had a similar game without hexes. Your's sounds better and more thought out. I like the hex idea. The one thing he had that might work for yours would be odds of random things being different. Maybe instead of a 6 sided use a 20 sided with something along these lines.
Relative to momentum

17 18 19 20 Straight
12 13 14 15 16 Left
7 8 9 10 11 Right
5 6 Sudden track reversal
4 Tornado splits in two
2 3 Disappears
1 Disappears to build stronger

You could also add some things or subtract some and use less or more number for something else. This keeps it random but keeps the odds on movement.

I would advise some research on tornadoes. I live in Tornado Alley and monitor ARES freqs during storms and I know a bit about how tornadoes move.

First thing you need to know is that tornadoes don't move as randomly as you might think. The vast majority of them move on a northeast heading. They don't ever "turn around" and go the other way, so you have to take this into account in your mechanic.

The average tornado travels about 35 mph so your ground scale along with the tornado's duration (an average tornado lasts 10 minutes) and game time scale will dictate how far it moves for how many turns.

Tornadoes form in the "hooks" of storm cells. How to do that can really just be random unless you're modeling the storm action as well. Might be a little overly complex. I think in the context of your game you can presume the players are already in a storm, so it's just a matter of placing a tornado.

When simulating a real event like a tornado, you can use real data to form the basis of your game. You are modeling something real on a smaller scale. If you were building a small model car, you would use a real car for reference; all measurements will be proportionately the same, just scaled properly. Do the same for your game. Get stats on tornadoes and scale them to fit the constraints of the game.

If I were doing this, I would make the appearance of a tornado random; roll some dice and cross reference it on the board grid. The definition of the tornado would be statistical. Roll 2d6 for ground speed; 7 = 35 mph, and anything above or below 7 increment or decrement by 5 mph. Seven is the most common result on 2d6 and 35 mph is the most common tornado speed. This will give you a very realistic stat spread for tornado speed since the chances of rolling other numbers are very close to the chances of real tornado speed variations. Results of 2 or 12 accurately represent the chances of a 5 mph or 60 mph tornado respectively occurring.

Direction is going to be NE 95% of the time, and about 1% of the time another direction. If played on a hex grid, roll d%; 1-95=NE, 96=N, 97=NW, 98=SW, 99=S, 00=SE. For other grid types, tweak as needed.

Duration can be 2d6 again. So the most common result of 7 means a tornado lasts 10 minutes (the most common tornado duration). Above or below 7 increment or decrement by 5 minutes and this gives you a pretty accurate statistical spread. Results of 2 or 12 accurately represent the chances of a 5 minute or 1 hour tornado respectively occurring.

All of this stuff can easily be put into table form for easy reference during play.

You now have to decide how much time a game turn represents and the scale of your map grid in order to figure out how many TURNS a tornado lasts and how far it moves per turn based on the stats above.

Actually, it's not. Everything is already worked out above. If you need the data in table form, I can type that up in 3 minutes for you.

As for car speed, you don't have to work out any relativity. Cars and tornadoes move in mph; they're already related. Speed is miles per (divided by) hour; distance/time. All you need to do is decided what a "mile" is in your game (hexes or whatever) and how long an "hour" (# of turns) is in your game. How big you want your map to be and how large of an area it represents will dictate these things. It's all just a matter of scale.

As for tornado frequency realism, don't worry about it. The game is about chasing tornadoes so you'll want them popping up more than usual. Just raise the chances of them occurring so that there are always a couple on the board.

You have a great idea for a game here. Don't be frightened by its perceived complexity, it's actually very simple. Just take each step IN ORDER. Most of your mechs will be defined by something else; each thing is a building block for the next. Start at bottom, build up. Since your map is defining things like distances, start with the map. Since speeds are determined by distance and time, do time next. Once you have distance and time, you got speed and speed dictates movement for everything; tornadoes AND chasers.

Make your map and time increment factors of the above with playability in mind. If a hex is 5 miles across, it makes your life easier for dealing with speed increments of 5 mph. Similarly, if a turn represents 5 minutes....

If you have 24" x 36" map with 1 inch hexes, that represents an area of 120 miles by 180 miles - a decent (and fairly realistic) sized tornado area - presuming 5 miles to the hex. Throw in a couple of interstates, a few state highways, and a load of county roads and you're good to go. Add gas stations, trailer parks, and the ilk as you see fit.

If you use numbered hexes, your random tornado placement gets simpler.

I love your idea and am willing to help you out in anyway when you get back.

Maybe. This is going to depend on playability factors more than game constraints, but it's a good possibility considering some other things you need to deal with below. All you really need to do is weight your spawn roll so that the odds are in favor of areas on the southwest quadrant of the map.

Not sure what you mean by this, but it's a little too vague to determine movement; more on that coming.

That seems pretty reasonable and easy to deal with. It will also come in handy later if you want to consider the possibility of the tornado changing direction. It's realistic in that tornadoes can veer a little left or right and your die allows for that.

Distance over time. If a tornado's ground speed is 35 mph, then it moves 35 miles in an hour. If your hex is 35 miles across, then it moves one hex in an hour. Problem is, tornadoes RARELY last an hour, more like 10 minutes, so your tornado isn't going anywhere. So make your hex scale smaller and your time scale smaller.

If your hex is 2 miles across, a 35 mph tornado moves 18 hexes per hour, 35/2=17.5, round up. If a turn represents 6 minutes of real time (10 turns per hour), then the tornado moves 2 hexes per turn, 18/10=1.8 round up. You can base other speeds around this median value.

That's a possibility and is going to happen. But, it's not going to happen to all players all the time. Plus, more tornadoes are going to spawn out of this supercell storm pretty darn quick and the next one might be right on top of the player who was too far away for the last tornado.

Another thing to consider is that tornado chasers usually have a pretty good idea where tornadoes are going to form. They're watching radar and listening to NOAA so they know where to look. They have a "head start" and you could incorporate this into your game.
There are precursors to tornadoes. Wall clouds form, then rotation starts, a few more things happen, and then a tornado forms. In your game, instead of placing a tornado figure right away, maybe you place a Wall Cloud marker instead. Then every turn after you can roll for rotation, and if you get rotation, then a tornado touches down the turn after that. That gives players a small head start on getting to the tornado simulating having radar and/or radios.

This also may ameliorate your need to have more tornadoes spawn in the SW (in question 1). If players have a slight head start, it balances out the fact that tornadoes might be farther away.

MPH is MPH. A 35 mile per hour tornado is as fast as a 35 mph car.

Thing is, modeling all those speeds makes movement too complicated. All you need to figure out is the maximum speed and then say "cars move UP TO x hexes per turn". On the interstate in pre-tornado conditions (thunderstorm), a car's top speed is about 80 mph for crazy tornado chasers. Assuming the same scale of 2 miles per hex then a car can move 40 hexes per hour, or 4 per turn. Cars have to go slower on county roads that are unpaved, so adjust your "speed limit" accordingly.

This isn't the question you're trying to ask, but you're close. See above.

How do you move half a hex?

Base it on your ground scale.

Personally, I think "F5" is great. Tornado purists might nit-pick that the Enhanced Fujita Scale has made "F5" an obsolete designation.
Other great tornado related words are "Supercell", "Squall Line", and "Outbreak Sequence".
Make a list of potential names you like and start asking other people what they think.

Possibly. That would be a good choice considering the frequency of tornadoes in that area.

That seems reasonable. Pencil it in.

Yes, but you mean SW instead of SE.
As for your 'figuring out probability' you did it right empirically. The way you 'set the spread' accounted for odds. You already knew that 7 was the most common result and 2 and 12 are the least common result and did it accordingly without needing to know the exact chances of any roll. Keep thinking critically like that and you'll do well.

By '3 or 4 speed choices' I take you to mean speed limits on roads and I think you're right.
As for gas management, that might get sticky; here's why:
If your map is 216 hexes, it's somewhere around 14x15 hexes. If each hex is 2 miles wide, that map only represents an area of about 28 miles by 30 miles. If a typical chase car has a gas tank capacity of 14 gallons and gets 20 miles to the gallon, the car can go 280 miles before refueling; that's 140 hexes at 2 miles per hex. That means a car can traverse either axis of the map TEN TIMES before needing to refuel. If a car moves 4 hexes per turn max, the car moves for 35 turns minimum before refueling.
Do you expect the game to go more than 35 turns? If not, there's no need to refuel.

If you want to incorporate a refueling aspect in the game, you might need a bigger map and/or cars with poorer mileage/smaller gas tanks.

Now you're beginning to understand the importance of map scale! It dictates just about everything you want to do with this game. However, you are going to run into some limitations and have to sacrifice reality with playability. It's likely that you'll have to fudge some numbers to get everything to work together smoothly when it comes to map size, hex size, and hex scale. There's a happy medium in there, you just have to find it.

You may be interested in a book entitled "Heavy Weather" by Bruce Sterling. It recounts the adventures of a hardcore storm troop chasing The Big Ones in a near-future slightly cyberpunk-tinged North America. It's one of my top 10 fave books of all time and I recommend it to you because it might give you some ideas for your game, particularly motivation and VC.

It could be much shorter than that. Tornado super outbreaks rarely last more than a few hours. This is because the supercell moves and changes. Your game "day" could be six hours or less.

That sounds reasonable. Can always adjust it as needed.

Oh, you'll continue to have opportunities to do so. As you tweak certain variables you'll see how it affects others.

Well, that's what happens in real life. To avoid this, increase the frequency of tornadoes. More tornadoes = more for players to do.

I can think of things, but you have to keep these side projects at a lower value. If the object of the game is to film tornadoes, you don't want players spending their time rounding up cows for VC. You could end up with a saddle point where the best strategy to win the game is NOT filming/chasing tornadoes.

Storm chasers don't do anything other than try to film tornadoes and scream like kindergarten girls (you've seen the show). Storm SPOTTERS on the other hand provide valuable info and service to NOAA/NWS and never scream.
Other things players could do as spotters might include retrieving livestock ("Loose cow!" - happens all the time), digging out trailer parks/reporting to emergency responders, reporting to NOAA/NWS, and related ilk. These are all things that happen AFTER a tornado though.

Downed trees and electrical wires are more common than damaged roads. A tree or wire down on a road could hinder a player for one turn while the road is safely cleared. In a case like this, you can have these obstacles, just don't let them be too punitive. Having to stop movement for the remainder of a turn is probably enough considering tornadoes are only going to last a few turns. You want this obstacles to be strategically interesting, not entirely preventative.

Look for it, it probably is. You'll love it.

Good idea. You can always add stuff once you have your mechanics down. It will be easier since a lot of the rules will already be in place and you can build from them.

I interpret "maybe roll twice" to mean rolling for another possible wall cloud. This is a possibility that will depend on playability. It's hard to know how many wall clouds generating tornadoes will make the game fun; too few makes a boring game, too many makes the game too easy. You'll have to playtest to find the happy medium. Start with one roll per turn and change it if needed.

Max two hex movement is probably OK considering the size of your board. The problem you MIGHT run into is players not making it to tornadoes before they "rope out" (dissipate). You haven't mentioned how long the tornadoes will last; the shorter the duration, the less likely players will get to the tornadoes. If you're set on keeping max movement 2, it will be easier to tweak tornado duration than re-do movement.

Cool. Some cotton dyed grey and twisted up might make a neat tornado. Low grade aspirin bottle cotton would be perfect. Soak it in watery grey paint and get some black/brown chunks in there for debris. Twist it around a wire armature and base it.

It's time for you to start testing the mechs to see if you like the interaction. Chase a couple twisters around your board and see if you need to adjust anything. Sounds reasonable so far, it probably won't take much.

Just remember that mph is mph. A car traveling 35 miles per hour is just as fast as a tornado traveling 35 miles per hour.

It doesn't make any sense that a car going 60 mph would move more hexes (3) than a tornado going 60 mph (2 hexes).

Tornadoes dissipate over time. Tornadoes also never last indefinitely. You can end the tornadoes randomly if you'd like or after a certain number of turns.
Keep in mind that if you do it randomly you will have tornadoes dissipating the turn after they're generated on occasion. Conversely, you will have tornadoes that last until they're off the map, so there's no reason to have a separate "lasts indefinitely" category to begin with; random already produces that result.

Speed doesn't determine distance. Speed is a function of distance; miles (distance) per hour (time).

If your map scale is 2 miles per hex, and you want to have a tornado travel 200 miles, you'll need 100 hexes to do so. If those are 1" hexes, that's a map at least 8 feet long. With half-inch hexes, it's 4 feet long.

Sounds perfect. How big are your hexes going to be?