Hiking Difficulty: MIDE, SAC and Why “Moderate” Means Nothing

Why difficulty is subjective

Two people can walk the same route on the same day and describe it in completely incompatible terms. One calls it a stroll; the other had a miserable time. Neither is lying. Perceived difficulty depends on at least five variables that are not in the track file:

• Fitness: the obvious one, and still the thing least often stated in a route description.
• Experience: an airy section is unnerving the first time and routine the twentieth. The terrain hasn't changed — the person crossing it has.
• Head for heights: this correlates with neither fitness nor strength. A two-metre step with a drop beside it can completely stop someone who climbs 1,500 m of ascent without breaking sweat.
• The day: the same route in fog, in soft snow or at 35 °C is a different route. Nearly every grading system implicitly assumes good conditions.
• Context: going solo, with children, with a group of mixed ability, or in a hurry to get back completely changes your margin for error.

Which is why “easy / moderate / hard” labels are close to useless: they compress all of the above into a single word, and every website and every club calibrates that word differently. Serious systems do the opposite — they separate the dimensions instead of merging them.

MIDE: the Spanish standard

The Método de Información de Excursiones (Excursion Information Method) was created by Alberto París Roche in 2002, as part of the Aragonese Mountaineering Federation's “Mountains to Live Them Safely” campaign, and was later adopted by the Spanish federation (FEDME) as its reference system. It's what you see on the wooden information panels across much of the country.

Its great virtue is refusing to give a single overall grade. Instead it scores four separate things from 1 to 5:

• Severity of the natural environment: how hostile the setting itself is. Exposure to falls, extreme temperatures, remoteness from inhabited areas, how easily you could call for help.
• Navigation: how hard it is not to get lost. From an obvious waymarked path through to terrain needing map, compass and judgement.
• Difficulty of movement: what the ground under your feet is like. Wide track, footpath, scree, or sections where you need your hands.
• Amount of effort: the purely physical part, derived from hours of actual walking time.

That separation is exactly what you need to make a decision. A 1-1-1-4 route is a slog over comfortable, well-signed ground: purely a question of legs. A 3-4-3-1 is short and not very tiring, but can leave you lost in serious terrain. The second is far more dangerous — and a single “moderate” label would make them look identical.

Alongside the four figures, a MIDE panel gives the reference data: time, ascent and descent, horizontal distance, route type (there-and-back, circular or traverse) and the season the rating applies to. That last detail gets ignored constantly: a MIDE calculated for August does not describe the same route in February.

Trail colours in Spain: GR, PR and SL

It's worth not confusing difficulty with waymarking. In Spain, the markings on FEDME-approved trails don't indicate how hard a route is, but how long it is:

• GR (Gran Recorrido, long-distance) — white and red. Over 50 km, designed for multiple days.
• PR (Pequeño Recorrido, short-distance) — white and yellow. Between 10 and 50 km, a single day.
• SL (Sendero Local, local path) — white and green. Under 10 km.

A PR can be vastly harder than a GR. The marks are in fact registered trademarks of FEDME, managed by each regional federation, and an approved trail does imply inspected maintenance and signage — which is a genuine guarantee, but of upkeep, not of easiness.

How it's done elsewhere: the SAC scale

The most widely used system in the Alps is the Swiss Alpine Club hiking scale (SAC), also from 2002. It runs from T1 to T6 and, unlike MIDE, is a single figure — but one focused on something very specific: the terrain and the technique it demands, not the effort.

• T1 — Hiking. Well-made path, no exposure. Trainers are fine.
• T2 — Mountain hiking. Continuous path, steep in places, with some risk of falling. Trekking shoes.
• T3 — Demanding mountain hiking. The path isn't always visible on the ground; exposed sections. Requires sure-footedness and some alpine experience.
• T4 — Alpine hiking. Hands needed in places; easy firn snowfields. Solid alpine experience required.
• T5 — Demanding alpine hiking. Often pathless, with simple climbing moves and bare glacier. Mountaineering boots, plus basic ice-axe and rope skills.
• T6 — Difficult alpine hiking. Mostly pathless, climbing up to grade II, frequently very exposed. Usually not waymarked at all.

In Switzerland the scale is also painted onto the terrain itself: yellow markers for T1, white-red-white for mountain hiking (T2–T3) and white-blue-white for alpine routes (T4–T5). You can see the difficulty before you commit to it. Grades are fine-tuned with “+” and “−”: T3+, T4−.

Other systems you'll run into

• France (FFRandonnée): the same waymarking logic as Spain — the GR network in fact began there — with ratings for effort, technique and risk. The white-and-red GR flashes are identical on both sides of the Pyrenees.
• United States: easy / moderate / strenuous dominates, with no standardisation between parks; once terrain turns technical it jumps to the Yosemite Decimal System, whose classes 1 and 2 cover hiking while class 3 and up is scrambling and climbing.
• United Kingdom: traditionally descriptive, resting on the distinction between walking, scrambling (graded 1 to 3) and climbing.
• IBP Index: not an institutional scale but a numerical index computed by software from the track, widely used on route-sharing sites. It measures effort, not technique or exposure: a high number means hard on the legs, not necessarily committing.

What each one measures, in a sentence

This is the key to not comparing apples with oranges: these systems do not measure the same thing.

• MIDE: four separate axes — environment, navigation, terrain and effort.
• SAC: technical difficulty and exposure of the terrain, as one figure.
• GR / PR / SL: length and official approval. Nothing about difficulty.
• IBP: physical effort calculated from the track.

A route can be T2 and at the same time a MIDE effort score of 4: technically straightforward and physically demanding. And the reverse. So when someone says “it's a medium-level route”, the useful question isn't how much, but in what respect.

Rating a route yourself

Before setting out, even if you're not going to fill in a formal MIDE panel, it's enough to answer the four questions separately:

• How long will it take, and how much climbing is there? Both come straight from the track.
• Is it waymarked, or will I have to navigate?
• What's the ground like? Is there any section needing hands, or with real exposure?
• How far am I from being able to call for help if something goes wrong?

The first two are answered by the file itself: in GEPYX you get distance, elevation gain and the elevation profile as soon as you draw or import a route, and from there you can estimate timings with the methods covered in how to estimate how long a route will take. Since elevation gain is the figure that weighs most heavily in any effort rating, it's worth knowing how it's actually calculated: two apps can report very different numbers for the same track.

The uncomfortable conclusion

No system, however good, rates the person walking. MIDE describes the excursion honestly; what it cannot know is whether you are up to that excursion on that particular day. That part of the calculation is yours to make — and it's the only one that really determines how the day ends.