DE paper: extreme rain on rise?

[k-bob]

http://www.delawareonline.com/story/weather/2014/04/06/extreme-rain-events-rise/7405047/

 

[Chaz]

While we have a fairly short time span from Hurricane Floyd until present, I believe that high rainfall events are coming more often and they are negatively impacting our trout streams. Many of these events are somewhat isolated. Interesting data Bob, thanks for posting.

 

[duckfoot]

Climate change is real folks. As we used to say, "the hots get hotter, the colds get colder, the dries get drier and the wets get wetter".

 

[Biggie]

Yes, climate change is real. What we don't KNOW is what causes it.

 

[JasonS]

Article is meaningless nonsense. I'll wait to see if anyone else can point out why.

 

[salmonoid]

JasonS wrote:
Article is meaningless nonsense. I'll wait to see if anyone else can point out why.

I'm not sure that it is meaningless nonsense, but rather just a reporting of a small data set, of which my age is longer than the data set time period is. And its dangerous to draw long term trends from a decade's worth of data. Please enlighten us who are in the dark, (because of power outages, because of more frequent and violent storms, because of global climate change). ;-)

 

[JasonS]

Nah you pretty much nailed it. It's a ridiculously small sample size. And they're not just reporting on a small data set, they are drawing conclusions from it. It'd be like questioning the fundamentals of probability because you flipped a coin twice and both times it came up heads.

 

[k-bob]

interesting to recall some of those storms. I got my house in the month with the day of heaviest rain for 15 years, in an area with springs. nice

the article gives vivid examples of heavy rains in our region last 15 years. it also says that days with 2+ inches of rain are more common in DE since 99 without showing any older data as the "before" picture. I noticed that on first read and titled my OP "on the rise?"

it's a newspaper folks, and reporters aren't specialists and cant work for too long on each article. it would be careless to select and present the post 99 data if the pre 99 data look no different. I tend to doubt they did that, but it's a newspaper folks.. ...

 

[JasonS]

Right. Lets see a hundred year graph and then we can see how much of an outlier the last 15yrs have been.

 

[pcray1231]

Article is meaningless nonsense. I'll wait to see if anyone else can point out why.

They precede the statement by saying that temperature, snowfall, etc. has wild ups and downs. To anyone trained in statistics, that immediately tells you that there's a lot of noise, and due to the amount of noise, the sample size is too small to come up with reasonable control limits, i.e. any sort of an estimate of a "typical range".

They follow it up with extreme rainfall events. The same logic applies. Hence showing that it is too small of a sample to properly understand "typical" behavior.

Most of climate science is hampered by the same innate weakness. It's a noisy system, and signals are small, so the signal/noise ratio is just horrendous. To be statistically valid, that means you have to compare separate 20 or 30+ year time frames. In doing so, you can indeed identify statistically valid trends. But such trends are the cumulative result of sometimes a dozen or more KNOWN causes and an untold number of unknown ones, all acting in different directions but still dependent on one another.

To get anything real, you have to do a lot of averaging out, and then it loses significance to any one time or place. For instance, if you want to get meaningful data on temperature, one place is way too noisy unless you wanna use 100+ year time frames. So you average over the globe to reduce noise, allowing meaningful data in a mere decade. You then find that 53 places are warming and 47 are cooling. That is statistically real, not imagined, and carries scientific meaning. But what it means for your backyard is totally lost.

 

[k-bob]

whatever.. intense rains whether or not more common may have altered a stream if you haven't been there for a while or are working from an older description...

 

[Chaz]

A quick look at weather data from Allentown, which is the nearest NOAA station to me shows some similarities to the events in Del. but they aren't identical. As for the short data set, yes that was my first thought, but we can look at tree rings and other stored data and get a clear picture of what our climate has been over thousands of years.
Whay I can say is that I've been on this planet for 60+years, and these major events didn't come as frequently when I was a kid as they do now. Climatologically speaking 60 years is a very short time, even though many of you weren't born yet it is changing.
Just look at the number of hurricanes we've had over the last ten years, and you can see the difference, we use to get maybe a hurricane hit PA. once every couple of years, and a big one maybe every 10 to 15 years. Since 2005 we had a much higher frequency of hurricanes hit PA. and they've been major events when they've happened. Is it because of global climate change, maybe, maybe not. But something is going on.
Of course there will always be deniers.

 

[k-bob]

Doesn't matter whether it was random or whatever, I fish in eastern sullivan county. The area got 10 inches of rain over a several day stretch in 2011 (page 10 below) when streams already had water from a 3+ inch rain a dozen days earlier (page 9 below).

Info on the rainfall totals in E Sullivan makes me less interested in older fishing books, etc, because that much rain could have changed stream structures up there.

http://www.nws.noaa.gov/om/assessments/pdfs/LeeSusquehanna12.pdf

 

[Chaz]

k-bob wrote:
Doesn't matter whether it was random or whatever, I fish in eastern sullivan county. The area got 10 inches of rain over a several day stretch in 2011 (page 10 below) when streams already had water from a 3+ inch rain a dozen days earlier (page 9 below).

Info on the rainfall totals in E Sullivan makes me less interested in older fishing books, etc, because that much rain could have changed stream structures up there.

http://www.nws.noaa.gov/om/assessments/pdfs/LeeSusquehanna12.pdf

And that's the point, these events have long term effects on streams.

 

[duckfoot]

Everyone's arguments and comments here are valid.

However, when I look at data like this, I think of how it changes water chemistry further down the stream because mountain waters move faster and wash things down to the wider, deeper (interpreted slower) water where an entire sediment layer and/or chemical balance can influence a lot of things.

Sure, a creek might change course, get big rocks in an old hole and carve out new holes, but the river it feeds is going to collect all that junk and runoff. I'd argue it's the slower-moving mouths that bear the brunt of this weather pattern.

 

[pcray1231]

Historically speaking, tropical systems in the northeast are in a somewhat active period. But not abnormally so. We had a similar active period in the 70's, which included Agnes, perhaps the most damaging storm in PA ever. Another similar period in the early 50's.

The most active period on record was 1900-1910. And back then they only counted storms with major wind. Excessive tropical rain, like Lee, was just "rain". We're more aware of what's remnants and what's not these days.

Not to discount that tropical impacts could rise due to warming. The logic makes sense. But 0-20 storms a decade are all within normal parameters. Any real effect so far is lost in noise. You can't take a few events and then say " see". We won't know if this is just noise or part of a trend for 30 plus years.

But that, apparently, doesn't sell newspapers like sensationalism does.

 

[Van_Cleaver]

I'm not even going to get into the facts/sampling etc. arguments. My observations is this: In the last several (especially the last few) years, we have had a huge no. of rainfalls events of two in" or more. Anymore a rain (nice on and off moderate) like today's seems to be the exception rather than the rule. In my 60 plus years of data I can only say for sure that both of the streams I grew up with (Pickering and French Ck.) are but a shadow of what they once were. Pickering more so do run off and dewatering from wells etc. These days when most streams are near median flow they appear to be robust as the median flow now is not even close to what is was twenty or thirty years ago.

 

[k-bob]

"We won't know if this is just noise or part of a trend for 30 plus years.

But that, apparently, doesn't sell newspapers like sensationalism does."

makes sense to me, but of course nothing sells newspapers like sensationalism does. that's why my OP identified the source as a DE newspaper and ended with a question mark.

 

[pcray1231]

Fair enough.

Yes, the last few years have seen a higher than average amount of 2+ inch storms, including tropical storms.

1. Abnormally high number? No. Not yet. Range is within historical "noise". But if "higher than average" either gets a lot higher, or else sustains over several decades, it becomes statistically valid and indicates that a change has taken place.

2. Due to global warming? You gotta answer IF before attacking WHY.

And I am one who considers global warming to be absolute fact, thinks humans as a contributing cause is extremely likely, and that humans as the PRIMARY cause is more likely than not.

But I'm trained in statistics and chaotic systems, and know that the effects on any individual outcome (such as storms over 2") is highly variable and uncertain, and recognize that human nature is to try to glean signals from what actually is nothing more than noise. It doesn't help that most of the public gets their information from the media, who loves to tap into political controversy. The politics end of this is that BOTH sides are misrepresenting science to further their pre-determined agenda. One side to hype the effects of global warming. The other to deny it outright.

Listen to neither. If your position pisses off both sides of the aisle, you probably got it about right.

 

[k-bob]

more extreme rain spells in our area? who knows, but interesting chart:

http://www.epa.gov/climatechange/science/indicators/weather-climate/heavy-precip.html

my real point is hyperlocal and from undisputed data in the last ten years: the loyalsock area was whacked with sharp enough rain spells to change some streams