Tracking the Deluge...the temperature of rain

[Team9nine]

Been doing a fun little experiment the past 7-10 days and thought I'd reproduce it here, kind of in diary form. Got to take advantage of the open water we've been fortunate to have.

January 7 at 7:22 PM

 

Had a few minutes to stop at a pond after work. Wanted to do a little science experiment. Forecast is calling for 3-5 inches of rain for our area from Thursday through Saturday. We are also supposed to be near record highs (almost 60) for a couple of those days.

 

So what is the temperature of rain? If it rains on a warm day, is the rain the same temperature as the air? If so, will our near freezing lakes suddenly become spring temps again? Will the warmer water just float on top of the cold water underneath and eventually just wash away through the normal draining process, leaving cold water lakes again afterward?

 

I'm speculating that the rain will be about the temperature of the dew point, whatever that happens to be during the 3 day storms. And given the amount of rain, some of that cold water will be mixed sufficiently that we should see warmer lake temps once it is all done...but how warm? I needed a baseline measurement before all this starts, so I grabbed a temperature probe and got that answer: 40.1 degree surface temp in this usually tough, cold water fishery. It was a bonus to land 3 bass in the process given I only had about 30-40 minutes.

 

Now I wait...

 

 

 

January 9 at 7:30 PM

 

Picked off 5 fish right at dark, just before the first drops of liquid mayhem began descending on the area Now we wait for the deluge to end in about 72 hours, then see what the damage is. Looks like they did split the storm with the worst parts going north and south of us, but still enough heavy stuff to trash our waters from the looks of it. Hoping to be able to get the resulting water specifics Sunday.

 

 

January 11 at 4:31 PM

Edge of the back side of the cold front has started moving through. Air temps have dropped 17 degrees in the past two hours. Prolonged cold air overnight will affect surface temps, so I stopped at a couple places to check on water conditions to see what is happening. Total rainfall in the area was 3.3 inches, and everything is flooded.

 

Over the past 24 hours, our dewpoint has been between 52-59 degrees. I checked a large, shallow pond I have been fishing a lot lately (but not the exact same pond as the initial temp trip from a few days ago). The surface temp there at mid-pond was 9.7 degrees C, or 49.5 F. Probably safe to assume it was also in that near 40 degree range at the same time.

 

I wanted to check the temp of just the rain in general, so I also stopped at a local creek that is severely flooded. It was a tad warmer at 10.5 deg. C or 50.9 deg. F. The pond is likely cooler from all the mixing with the cold water. That wouldn't occur in the creek since the rainwater would basically flush everything out continuously. Clarity at both places was well stained, but not muddy. Average visibility in the 4"-6" range, at least closer to shore.

 

Hoping to hit the original pond tomorrow for a bit and see if it's the same. Also going to try and catch a fish Guessing most everything in the immediate area will be pretty ubiquitous.

 

 

 

January 12 at 8:12PM

 

Had sleet/freezing rain overnight, and high today of 36, so guessing surface temps will cool off quick. We'll know tomorrow.

 

January 13 at 7:26 PM

Stopped for a quick check after work. Water temps, at least on the surface, have continued to drop. The one I checked today was pretty consistent at around 7.1 degrees C (44.8 deg F.). Even the incoming water from the main drain that feeds it is the same temperature, so we've lost several degrees over the past 2 days. This isn't too surprising considering that for the past 48 hours, our temps have held fairly steady between a range of 33-41 degrees, with almost no sun exposure. Water color is well stained with about 2-3" of visibility. You can get a pretty good idea from the first picture. Made some casts with a tiny, slow moving blade bait that worked well right before the storms with no signs of success, so quickly switched to the jig/plastic and just pitched a few key areas. This worked, as I caught 3 bass in a fairly short amount of time. Hoping to catch a little warming trend tomorrow and expand on the area. See if I can get a few more fish to bite in this cold, murky water.

 

 

Jan. 14 at 8:00 PM

Frost overnight and minimal sunshine meant the ponds continue to cool, now down to 6.3 deg C or 43.3 degrees F. Parts of the pond were still muddy at 1-2 inches of vis., up to a good 6 inches the further away you went from the incoming water. Did manage 6 bass, all mostly smaller, and all displaying the very pale coloring often seen in cold, muddy water conditions. Interestingly, most of the fish came from the murkiest water, and were surprisingly aggressive, either thumping the bait or grabbing it and hauling butt. Wasn't expecting that.

 

[Paul Roberts]

On 1/14/2020 at 6:41 PM, Team9nine said:

Been doing a fun little experiment the past 7-10 days and thought I'd reproduce it here, kind of in diary form. Got to take advantage of the open water we've been fortunate to have.

Awesome.

 

This is why I take temperature profiles, and have come to try to identify a "core" water temperature. When a pond is 40F, the entire pond top to bottom will be 40F. That's a mass of cold water, and the core temp is 40F. Anything colder or warmer will sit on top of that 40F core. Only thing that can change that to any measurable degree is incident radiation from the sun, which is now too low in the sky to affect water temps much, and on incident banks, and only skin deep. The other option is a heavy warm rain. But, my guess was it would have to be a lot of warm water to affect that core temperature very much. So, it would have been best to have a profile, or cheat and take a temp at ~4ft, to get an idea of what the mass of water out there, the "core", would be.

 

That was a substantial change you recorded, +9F change at the surface. My guess the majority of that was at an inlet (?). Was it enough to draw fish up? Came and went so fast though, which is not surprising for January. Sounds like those last fish you caught were up in the inflow, which was not only the muddiest, but also warmest? I'm guessing that it was still the warmest water in the place, a bit above "core", and was warmer yet the previous days.

[Fairtax4me]

Interesting subject and thanks for taking observations. 
This is something I’ve been slightly paying attention to the last few months as well. We’ve had several moderate rains that at first kept most smaller lake temps in the low to mid 40° range. (Vs falling into the upper or mid 30s due to overnight temps during the same time period) 

 

Last week we had a night of heavy rainfall, around 1-1/2 to 2”. Several of the smaller lakes I normally fish were in the low to mid 40s surface temp. Knowing that many of them would soon be full of mud I went to one of the smallest which is fed by a somewhat large creek, and normally this lake stays pretty muddy. 
Over the course of the previous several weeks the water had cleared considerably with groundwater inflow, and only a few light rains. I fished here about two weeks ago and water temp was around 41° with visibility about 2-1/2 to 3 feet. 
 

I decided to fish here the next morning which was only a few hours after the rain stopped. The bulk of the rain had come in  about midnight, and I put on the water around 10am. 
 

There was a very clean cut line between cold clean water, and warm muddy water that was flowing in and down the spillway of the dam. The “cove” at the bottom end of the lake was still very clean. Approx 4ft of visibility, and water surface temp was 39°. 
 

In the muddy water that was coming in, water temp was 45°, and visibility less than 6”. 
 

This is the best photo I have showing the demarcation line between warm muddy and cold clear(ish) water. 
 

I also noted that in the cold water fish marks were on or very near the bottom anywhere from 10-18 feet down (18’ being the deepest point in this lake). 
But in the warmer water I marked baitfish and bass as shallow as 3 feet and as deep as 16ft, but all were suspended in the much warmer water. 
Nothing would eat, spent 4-5 hours fishing various different lures without a bite. 

[Paul Roberts]

15 hours ago, Fairtax4me said:

Interesting subject and thanks for taking observations. 
This is something I’ve been slightly paying attention to the last few months as well. We’ve had several moderate rains that at first kept most smaller lake temps in the low to mid 40° range. (Vs falling into the upper or mid 30s due to overnight temps during the same time period) 

 

Last week we had a night of heavy rainfall, around 1-1/2 to 2”. Several of the smaller lakes I normally fish were in the low to mid 40s surface temp. Knowing that many of them would soon be full of mud I went to one of the smallest which is fed by a somewhat large creek, and normally this lake stays pretty muddy. 
Over the course of the previous several weeks the water had cleared considerably with groundwater inflow, and only a few light rains. I fished here about two weeks ago and water temp was around 41° with visibility about 2-1/2 to 3 feet. 
 

I decided to fish here the next morning which was only a few hours after the rain stopped. The bulk of the rain had come in  about midnight, and I put on the water around 10am. 
 

There was a very clean cut line between cold clean water, and warm muddy water that was flowing in and down the spillway of the dam. The “cove” at the bottom end of the lake was still very clean. Approx 4ft of visibility, and water surface temp was 39°. 
 

In the muddy water that was coming in, water temp was 45°, and visibility less than 6”. 
 

This is the best photo I have showing the demarcation line between warm muddy and cold clear(ish) water. 
 

I also noted that in the cold water fish marks were on or very near the bottom anywhere from 10-18 feet down (18’ being the deepest point in this lake). 
But in the warmer water I marked baitfish and bass as shallow as 3 feet and as deep as 16ft, but all were suspended in the much warmer water. 
Nothing would eat, spent 4-5 hours fishing various different lures without a bite. 

Wow! Great set of observations -timely temperatures, and sonar readings too. You hit it just right to see it happen. Conditions can best be understood by thoughtful measurements. Thanks for sharing this, Fairtax. 

 

With a 39F ST, you wouldn't need to take a profile -the whole column is the same. Anything warmer or colder, will sit on top of that mass of dense water. Winter clear water is mostly due to loss of both plankton and active decomposition suspended and circulating through the water column. I call it the "Winter Clear Water" period. It's the main reason why winter bass can be so beautifully marked. Your muddy water bass would probably be washed out in coloration.

[Fairtax4me]

8 hours ago, Paul Roberts said:

Wow! Great set of observations -timely temperatures, and sonar readings too. You hit it just right to see it happen. Conditions can best be understood by thoughtful measurements. Thanks for sharing this, Fairtax. 

 

With a 39F ST, you wouldn't need to take a profile -the whole column is the same. Anything warmer or colder, will sit on top of that mass of dense water. Winter clear water is mostly due to loss of both plankton and active decomposition suspended and circulating through the water column. I call it the "Winter Clear Water" period. It's the main reason why winter bass can be so beautifully marked. Your muddy water bass would probably be washed out in coloration.

Very much so. The bass in that particular lake are almost always “washed out” and have very little marking, especially the smaller bass, which can sometimes be completely silver with only a hint of difference in color on the back and lateral line. Hard to tell in photos but this bass was lighter to the eye than it appears. 
The water in this lake this year has been unusually clean, so the bass have started to take on darker colors than they usually have. 
 

Ive often wondered in late fall going into early winter how the colder rain affects lake temperatures. Logic says the cooler water should flow in and fall to the bottom. But I’ve also wondered if the water becomes stratified where there are layers of 80° surface, 70° in 20-40 feet , 60° somewhere in between. I know that when it starts to get very deep 60ft+ water temp tends to stay at a certain temp no matter what time of year or what temp inflowing water is, but it also tends to have very low oxygen levels so bass won’t typically spend any time there. 

[Paul Roberts]

I started to write that I'd never measured an inversion... but I may have. I'd have to look that up in my journals. I seem to remember measuring mixing following a snowfall. It was a shallow pond though and things equalize pretty quickly.

 

That's a healthy fish. Nice photo.