Glaciers at 27N?

I have been watching videos taken in East Nepal at approximately 27 degrees North and 5000 feet of elevation.

Knowing a little bit more than the typical layman about soil formation and soil profiles, I am immensely baffled by the deep soils on the steep slopes. I am also baffled by the heterogeneous nature of the soil with regard to particle size...from clay to heads-sized rock.

Just eyeballing it, 12' wide paddies and 18" of rise is a 15 degree slope.

There were multiple sequences of village people hacking out rice paddies on slopes of 10' of rise in 100' of horizontal or more.

The typical theories of soil formation are that soil is created out of native rock via thermal-cycle cracking or by erosion/abrasion. Thermal-cycle cracking occurs where freeze-thaw cycles occur or where there is significant day-night temperature differences, typically in areas with low cloud-cover and on slopes facing the equator. The depth of soils created by thermal-cycling are self-limiting as the cycles attenuate with depth.

An atypical source of soil is volcanic ash.

The native rock is angular and blocky

Much gravel in that soil

Soil that has been modified by water-based erosion is often highly stratified by particle size. Also, that soil tends to end up in the bottoms of valleys and not stay thickly trowelled onto the sides of the slopes.

Glaciated soils

Glaciers are bulldozers and mixers while water is OCD and sorts.

Valleys formed by glaciers tend to be "U" shaped while valleys formed by water tend to be "V" shaped.

There is more than a little bit of evidence (soil profile and depth) that 27N at 5000 feet of elevation was probably covered by glaciers at one time. In fact, thick soil is the result of retreating glaciers edging forward in the winter and retreating in the summer with each cycle leaving a ripple of thick soil.

That is mind-boggling. 27 degrees north is about the same latitude as Tampa, Florida. 5000 feet of elevation is not trivial. That might make a 20 degree F difference vs. Tampa. But still, glaciers!

One must surmise that those glaciers retreated long before humans were the dominant species on the planet...long before.

I wonder if any of my readers are geologists who would be willing to point out the errors in my thinking. 

---Added after sleeping on it: It occurred to me that the depth of the soil could be due to land-slides. The soil forms at higher elevations via normal weathering processes. An exceptionally dry year or series of dry years might allow fires to burn off the vegetation. Roots decay in thee soil and cannot hold it together. Rains come. The entire horizon of soil slides down the slope, mixing as it goes.

Nepal is also very active from the standpoint of earthquakes. You have to wonder how stable the saturated soil beneath the paddies will be with minimal roots stitching it together.---