AVA trail ratings
The trail rating consists of two parts. Both numbers speak to the difficulty of a trail but in different ways. The first is a number from 1 to 5 that indicates the incline and or elevation gain of the trail while part 2 is a letter from A to E that describes the trail surface.
A trail rated 1A will be one of the easiest trails offered, while 5E will be technically very difficult. There are very few trails rated 5E, most are 1A or slightly more difficult.
The trail rating is given for the standard 10Km distance. In many cases the shorter distances can have an easier trail rating. This is often noted in the sanction comments.
Part 1 - Incline and elevation
1 - Very small hills or very little stair climbing.
2 - Some moderate hills or stair climbing.
3 - Some significant hill or stair climbing.
4 - Lots of significant hills or stair climbing.
5 - Many steep hills.
Part 2 - Trail surface or terrain
A - Almost entirely on pavement.
B - A significant part of the route is on well-groomed trails with very few obstacles.
C - A significant part of the route is on somewhat difficult terrain (rocky/rooted paths or soft sand.).
D - A significant part of the route is on very difficult terrain.
E - The majority of the route is on very difficult terrain.
When determining elevation gain, if a route goes up for 50 feet and down for 50 feet and back up for another 75 feet, the cumulative gain would be 125 feet. This is over the entire route, so the hills are slight and would be rated 1. If this gain was due to stairs, then a rating of 2 would be more appropriate.
A route that is mostly on flat pavement would be rated 1A.
A beach walk would be rated 1C.
A route with moderate hills on well groomed trails would be rated 2B.