It depends on how long after the flood and whether the water table below the surface eventually stops providing water to the surface by capillary action.
Flooding events tend to both dissolve white surface minerals as well as deposit sediment so initially after the flood the surface is just a dirty brown as most of the water is absorbed into the soil rather than immediately evaporating. The flood basically washes the white surface from the top with the minerals being absorbed into the top soil layers. So on that short time scale flooding events make the surface less white.
Over time capillary action brings high salinity water to the surface where it evaporates leaving white minerals behind and thus the surface whitens over time. Thus during this stage the longer in time from the flood the whiter the surface.
Eventually however the soil desiccates enough that the water table is too low for capillary action to continue to bring mineral laden water to the surface and evaporate. At this point wind takes away white minerals and deposits brown minerals and without the capillary action to continuously replenish the surface with white mineral the surface becomes brown over time. So at this stage the more time since the flood the less white the surface.
Section 2.2 on page 5 of the article linked below gives good photos and explanation of the process on a different salt pan:
https://mdpi-res.com/d_attachment/remote...-00474.pdf
BTW, I learned much of this first hand the hard way some 20 years ago when I made the mistake in Saline Valley of thinking it would be safest to walk on the whitest part of the pan. No indeed, a really white pan means there is quite a bit of water under it keeping the surface nice and white with capillary action. Feet punched through into some of the grossest mud I’ve ever encountered…
Flooding events tend to both dissolve white surface minerals as well as deposit sediment so initially after the flood the surface is just a dirty brown as most of the water is absorbed into the soil rather than immediately evaporating. The flood basically washes the white surface from the top with the minerals being absorbed into the top soil layers. So on that short time scale flooding events make the surface less white.
Over time capillary action brings high salinity water to the surface where it evaporates leaving white minerals behind and thus the surface whitens over time. Thus during this stage the longer in time from the flood the whiter the surface.
Eventually however the soil desiccates enough that the water table is too low for capillary action to continue to bring mineral laden water to the surface and evaporate. At this point wind takes away white minerals and deposits brown minerals and without the capillary action to continuously replenish the surface with white mineral the surface becomes brown over time. So at this stage the more time since the flood the less white the surface.
Section 2.2 on page 5 of the article linked below gives good photos and explanation of the process on a different salt pan:
https://mdpi-res.com/d_attachment/remote...-00474.pdf
BTW, I learned much of this first hand the hard way some 20 years ago when I made the mistake in Saline Valley of thinking it would be safest to walk on the whitest part of the pan. No indeed, a really white pan means there is quite a bit of water under it keeping the surface nice and white with capillary action. Feet punched through into some of the grossest mud I’ve ever encountered…