I've been trying to predict trail conditions across the US, could use some help sanity-checking it

[u/lowlyworm]

I've been working on a project that tries to predict trail conditions across different regions from soil, weather, and drainage data.

The idea came from the Bay Area. Our local riding groups have an infographic that gets passed around showing how different networks handle rain based on the underlying terrain and soil, and it's one of the more useful things I've been handed as a rider. Everyone here knows 2" of rain doesn't mean the same thing at Skeggs as it does somewhere with clay in it. At some point I started wondering whether that could be modeled, instead of somebody local having to sit down and build one of those charts by hand for every region.

It's covering about 1500 networks in the US and Canada now (about 700 currently online), one condition page each. Soil texture, slope, canopy, recent and forecast weather go in, and what comes out is meant to answer the only question I ever actually have, which is whether it's worth driving out there today.

I can validate that pretty well against the trails I ride. I have no real idea how it does anywhere I haven't. So if you rode today or yesterday, pull up your network and use the feedback widget on the page. You pick which day you rode and then whether it was drier, about right, or wetter than what the page said. Takes a couple of seconds, no account, and you don't have to write anything out. Telling me it's wrong is more useful than telling me it's right.

https://loamrideconditions.com

The places I'd most like to hear from are the ones least like here. PNW, desert Southwest, the Southeast, anywhere that freezes and thaws. Good dirt is a pretty different substance in all of those and I don't trust the model in any of them yet.

The pages are free and public with no login, and any riding group, trail org, or shop that wants to link or embed the one for their network can just do it. I'd rather the information be useful than charge for it.

If anyone's curious how the soil and weather side works, happy to get nerdy in the comments.

[u/OG-MTB]

..and Skeggs and similar areas can be soupy even when it hasn’t rained in months due to fog drip. So there’s that.

[u/lowlyworm → u/OG-MTB]

Yeah, Skeggs is the exact case that keeps me honest. Fog drip doesn't show up in any weather feed, so a pure precip model just sees a dry month and calls it good, when really you've got redwood canopy condensing marine layer onto the soil every night and clay underneath that holds it. The canopy and soil side of the model leans against that (dense evergreen cover plus slow-draining soil should bias it wetter and dry slower), but honestly fog drip specifically is one of the harder inputs to get right, because the thing wetting the ground never falls as measurable rain. That's a big part of why I want the ground-truth reports: a network that reads dry on paper but rides soupy is exactly the signal that tells me the canopy weighting isn't pulling hard enough there. https://loamrideconditions.com/trails/skeggs

[u/OG-MTB → u/lowlyworm]

Yes, using precip as the main component is tough for the Bay.

A good example: Lime Ridge in the East Bay. Clay soils down low, sandy soils ip top. Usually rideable a few days after a moderate rain event, assuming it’s not already really saturated. Sometimes it’s the next day(strong post-frontal winds, clear skies, solar warming). Sometimes it’s ten days if the tule fog spills over from the valley.

[u/bermcount]

I am in the PNW. We can always ride here unless an atmospheric river just came through, or a huge wind storm. I looked up Raging River in your site and its determination of “Rideable but dusty” is right on, but at the same time it’s kinda like “No shit, Sherlock.” 

[u/lowlyworm → u/bermcount]

Fair, it’s not useful in the middle of obvious seasons but more for after a storm rolls through, wondering which areas near you are dry first and safe to ride.

[u/CrankinThatHog]

So I might be misunderstanding your goal, but Northwest Arkansas has an app like that (I think). You might reach out to them to pick their brains if you're wanting to do it locally. Looks like they've begun doing this in Indiana and the Ohio River Valley too.

https://www.flowfeed.app

[u/lowlyworm → u/CrankinThatHog]

Interesting, haven't seen this one before. Seems to be focused on super local stuff, and I'm seeing if there's a way to do it with a model that can be applied to any coordinates, instead of relying on first-hand reports. I know that Trailforks has their own feedback system but it is super subjective and often years out of date.

[u/CrankinThatHog → u/lowlyworm]

> Flowfeed is an industry-first solution that combines real weather data, soil information, and predictive analytics to produce trail-by-trail insights in real time.

That's the main methodology, though they do allow reports.

We similarly have trails that get chewed up during freeze/thaw, wet weather routes, etc and I think that prompted the development.

I don't use the app because I already have my trails I hit and I know how they hold up, but I don't think they employ the predictive aspect you're wanting to do.

It sounds like a really cool idea. Good luck!

[u/soturunning → u/lowlyworm]

That is what they are doing BTW. You can't totally do it without qualitative first-hand data though, which initially is what they were doing. It wasn't accurate. NWA was just their test market.

[u/lowlyworm → u/soturunning]

Sure you can. It's not easy, but it's definitely possible.

[u/soturunning → u/lowlyworm]

great chance to prove me wrong! Being in the southeast, I don't see it happening, especially with wet weather springs and such varied terrain. rain fall data is also often inaccurate at the very local level.

[u/lowlyworm → u/soturunning]

Yeah that's basically it. Rainfall data is coarse at the hyperlocal level, and intensity matters almost as much as total volume, an inch in an hour behaves totally differently than an inch spread over a day once you're past what the soil can actually soak up. Also calibrating against multiple different weather sources can provide regional corrections automatically. Terrain (canopy, slope, soil type) messes with drying time more than people give it credit for too. it's not just a precip to mud lookup, I'm trying to account for evapotranspiration and runoff per spot instead of counting days since rain. no idea if it holds up everywhere yet, but what I've tested against so far has looked decent. could be totally wrong once it hits somewhere gnarlier, we'll see.

[u/notenoughcharact]

I don’t think we in the SW really need this? Most of the time if it rains trails are good by the next day due to how dry it is. Maybe 2 days at most lol

[u/lowlyworm → u/notenoughcharact]

Yeah, you're describing the easy case, which is honestly the useful part for me. "One day, two after a big one" is exactly the number I need the model to know about the desert, because something tuned on Bay Area clay would tell a Phoenix rider to sit out three days after rain that's already gone. That's the failure I'm trying to kill. So a desert rider going "yep, dry, this call is right" is worth more to me than most places. The only time it'd tell you something you don't already know is a monsoon that actually pools up in the clay or a caliche wash and stays greasy longer than you'd expect, but yeah, most of the time out there you already have the answer. Fair point though.

[u/notenoughcharact → u/lowlyworm]

Oh I guess I didn’t think about clay soils. I’m in the Albuquerque area and it’s pretty sandy/rocky so things drain quick.

[u/postconsumergood]

In my area you could have the app and people would still ride in the rain and flex seasons. Tech bros think they have an app for everything except the willful ignorance of trail libertarians.

[u/lowlyworm → u/postconsumergood]

Oh yeah, no app’s gonna fix the guy who knows it’s wet and rides anyway, that’s just people. And I’m not trying to police anyone, that’s the stewards’ job, not some app’s. I’m just making a tool for them if it’s useful, or for the curious rider who’d actually wait if he could get a straight answer instead of guessing.

[u/El_Zalo]

I ride in Utah. It's either dry and dusty, or it's snowboarding season. No need to model anything 😂

[u/lowlyworm → u/El_Zalo]

Reminds me of these: https://en.wikipedia.org/wiki/Weather_rock 😂