I had to check...It appears the scientific consensus is that snails can sense light, like lightning, and vibrations, like thunder, including in the human visual and auditory ranges, and more, through several tissues:

The Snail’s Sensory Organs

Snails do not have ears like humans or many other animals. However, they do have sensory organs that allow them to detect vibrations, changes in pressure, and some sound waves. Here are the main sensory organs of a snail:

Tentacles – The two tentacles on a snail’s head contain sensory organs called ommatophores. These can detect chemical cues in the environment, as well as some vibration and movement.
Eyes – Snails have two sets of eyes – the larger, lower eyes can sense light and dark, while the smaller, upper eyes can detect movement.
Osphradium – This sensory organ behind the snail’s head can detect chemical stimuli in water. It is thought to help with sensing predators.
Body – A snail’s body can sense vibrations through sensory cells in their skin and shell. Their soft bodies amplify vibrational signals.

While snails do not have ears, their combination of sensory organs does allow them to detect some sounds and vibrations in their environment.

https://www.restonyc.com/can-snails-hear/

I'd like to know, what, if anything, is the snail thinking about the storm.