Atmosphere Comparison

[Jim]

The endless chatter of weather.

[johnlp]

Roosevelt lake is up 1.07 feet since Saturday. The lake is 33.58 square miles. There are 640 acres per sq mile. There are 325,851 gallons per acre foot of water. Rounded off that comes to 7.49 billion gallons of flow into the lake since Saturday. Impressive. The lake is only up 1%. It holds quite a bit.

[Jim]

@johnlp
And that is good, but I was basically stating that I wonder if there will be a large spring run off next month or so, as I don't know that the Salt and Black River watersheds have a large snow pack, given the precipitation this winter.

[johnlp]

Agreed. Snow is key.

[Jim]

SRP knows the street value of that mountain.

[chumley]

Roosevelt has risen 5 feet in each January and February. Unless something extraordinary happens in the next couple of months that significantly increases the rate of input above what it has been these past two months, there's no chance of it filling this spring.

[chumley]

With the rain last weekend, I was expecting to see more of an impact in the latest drought report, but there was essentially no change across Arizona. Large swaths of central and southern California on the other hand ...

I've put together this week's map vs. last week, as well as the map from the start of the water year in October. It's been a good winter so far!

http://droughtmonitor.unl.edu/

[Jim]

From the current drought monitor:

A shallow snowpack with low SWE along the eastern portion on the Mogollon Rim in eastern Arizona prompted the introduction of a spot of D1.

Actually, our fair state has had an increase in drought per the discussion and map, and a lack of snow water equivalent, or snow pack, in the eastern Mogollon Rim and White Mountains, is the reason. This is pertinent to my earlier questions about the potential March snow run-off and Roosevelt lake.

[big_load]

It's about 30F above average in NJ today. By the end of February, I think we'll have had at least 10 days that were 15F or more above average and only two or three that were more than 10F below average. The heat could lead to some late winter brush fires.

[chumley]

A week ago the forecast called for the potential of a moderate storm today and tomorrow. As the week went on, the models all backed off on the available moisture for the storm. Then yesterday the models came back to a more aggressive system once again. Now today they are calling for 2-3" of rain (or snow water equivalent) in some of the mountain locations, and over a foot of snow above 7000 feet (up to 2 feet higher up).

Over half an inch is forecast in the Phoenix valley and over an inch in the northern/eastern Tonto foothills. Let's keep this winter going!

[SuperstitionGuy]

Let's keep this winter going!

In the meantime the sun is a shining in Apache Junction with no sign of rain.
Fake news?

[chumley]

Weather forecasters have been getting it wrong since the first time the Earth was flat.

[flagscott]

Let's keep this winter going!

In the meantime the sun is a shining in Apache Junction with no sign of rain.
Fake news?

Only if it was in the New York Times, CNN, or CBS.

[ALMAL]

@chumley
Hopefully very short or no fire restrictions this spring, like 2015...

[chumley]

@ALMAL
In my recollection that has much more to do with what happens in April and May than February and March.

[rcorfman]

Let's keep this winter going!

In the meantime the sun is a shining in Apache Junction with no sign of rain. Fake news?

Well it was cloudy all morning in North Phoenix and is raining now.

[CannondaleKid]

Hopefully very short or no fire restrictions this spring, like 2015...

More rain = more vegetation growth... and when that vegetation dries out who knows, it could be a bad year for fires.

[flagscott]

Hopefully very short or no fire restrictions this spring, like 2015...

More rain = more vegetation growth... and when that vegetation dries out who knows, it could be a bad year for fires.

That's not really true--at least for this year. Scientists with a lot more patience than me have looked at fire histories by measuring tree rings, and in ponderosa pine at least, fires generally occur in the summer after a dry winter/spring, not a wet one. But having a couple of wet seasons followed by a dry season can increase fire severity. So watch out for 2018 if next winter turns out to be dry.

That said...the old patterns may not hold up anymore. A new paper out today basically says that thanks to humans, wildfires are happening way outside their normal seasons, and dryness is increasingly less important than the sheer number of idiots lighting fires. http://www.npr.org/sections/thetwo-way/ ... u-s-humans

[Jim]

Hey, did anyone else remember that grass grows in lower elevations and one of the states biggest fires was a rapidly spreading grass fire in May or June of 2005, just north of Black Canyon City and after a very wet winter that spurned low elevation fine fuel growth? I wasn't even here, wouldn't be for a year, but I remember this.

[chumley]

Ponderosa forests and scrub desert are totally different. In my experience rainy winters cause high summer fire danger across the deserts but not in the forests.

In other news I see lots of 2-3" rain totals north of Phoenix. More than a foot of snow in Flagstaff and Snowbowl reporting 21" storm total so far, and expecting a few more inches before it ends. Not bad.

[flagscott]

Hey, did anyone else remember that grass grows in lower elevations and one of the states biggest fires was a rapidly spreading grass fire in May or June of 2005, just north of Black Canyon City and after a very wet winter that spurned low elevation fine fuel growth? I wasn't even here, wouldn't be for a year, but I remember this.

I'm assuming this was a response to me. My comment above was specifically referring to ponderosa pine, as I mentioned. Here's another study, a classic, showing the same result--more fires happen in dry years than wet years: http://digitalcommons.usu.edu/cgi/viewc ... arkbeetles

As for other parts of Arizona, it's more complex. This paper: https://www.researchgate.net/publicatio ... ran_Desert makes a strong case that you need two consecutive wet winters to significantly increase the likelihood of fire in the Sonoran desert. One wet winter alone does not have much of an effect.

In grassier areas, like Southeast Arizona, the relationship varies by elevation. Higher up (above 5000'), prior-year precipitation increases fire frequency. Lower down, fires happen more when it was wetter during the year before or the same year: https://www.researchgate.net/profile/Mi ... 000000.pdf There's evidence for the same in prairie areas that tend to dry out seasonally in the summer.

The studies I link to each studied hundreds of fires over decades or centuries. I would suggest not jumping to conclusions from any individual fire or even any individual fire year.