ROADS
The biggest, meanest tornadic storm in the world is useless to a storm chaser unless he has enough good roads to follow the storm and obtain a view of the storm's updraft base. Paved roads are much preferred, though chasers will drive on gravel roads if conditions are not too bad. Dirt roads are generally avoided since they can turn into slippery mud during a rainstorm. I do not have a map of road density per county for the US (If you know of one, please tell me).
The best rural road network across "
Chase Alley" exists in west central Texas in the agricultural areas around
Lubbock. This area is the ultimate in "chaser nirvana" with grid of paved section line roads just about every mile. Texas has the best rural road network in the plains. Roads which are gravel in Kansas, Nebraska and Colorado would be paved if they were in Texas.
Another region with a very good rural road network is the "
Corn Belt." (eastern Nebraska/Dakotas to western Ohio). Although most of the "Corn Belt" is not technically located in my definition of "
Chase Alley," it is relatively flat terrain and has a high tornado frequency. It is the second best storm chase region after the Great Plains.
The region with the worst road network in or near "
Chase Alley" is the
Sand Hills region of Nebraska. There are very few roads and many great storms have been missed in this region. Other areas in or near "
Chase Alley" with a poor road network include: southwest Texas, eastern New Mexico (except for the Clovis/Portales area), parts of eastern Colorado, eastern Wyoming and the western Dakotas. Many of these areas are still chaseable, however, due to flat terrain and/or great visibility and lighting.