I have put the 3 lumen red light down on the ground (in the cool half the year) and I can't see it beyond 10-15 yards and that is walking away from it, turning around and walking back.
With the three lumen light on green, I can see to walk in the woods like it was day time - which isn't saying much, our woods are very thick with lots of underbrush and locust trees and branches and tree trunks on the ground. Slow going in day or night. But the 3 lumen on green is amazing and allows full speed for one person in the woods. Each color is visible a bit farther out in this order Red, Blue, Green, White. And if they are reflecting off something, then visible farther out. But the 3 lumen light is useful for my purposes of navigation and messing with gear without using NV or thermal.
If you are hunting with white lights or engaging critters that shoot back or just spotting with white lights then much brighter lights are indicated, but I'm not doing those things. I do use white lights when I am working at night in the pastures ... using the tractor or burning etc. But I do not use white lights for hunting except for emergencies.
If you are out searching for snakes at night, I guess you would want a really bright white light. But I've never searched for snakes at night, so I'm not sure. I wear good boots and hope for the best. According to the critter books I have for this area - including the one the US Army hands out to the troops at Fort Riley, there are supposed to be about 400 cotton mouth on my land, but I have not seen one. I see plenty of other snakes, but I don't bother them unless they are in our buildings, in which case I take them way out in the pasture and let them go. I've found one juvenile rattler and I took it way out in the pasture and let it go. Most of the snakes I find in our buildings are going after rats ... and I'm on that team also, so I just take them out of the buildings and they head off.
I would think searching for snakes at night with white lights would be a tough business though it hasn't occurred to me to try it. But I presume if you were doing that you wouldn't be hunting for other critters because they would tend to see the white light and move away. Hence if I were hunting I wouldn't be using white lights to search for snakes and if I was using white lights to search for snakes I wouldn't be hunting. But perhaps I am off base here - it just never occurred to me to try it!
I do think I've "heard" a snake near me twice at night in 5 years of going out at night. But my action was to stop and listen more closely. The noise stopped and I moved away from it.