This year is shaping up, water wise, very similar to 2011

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drcalderwood

drcalderwood

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With the storms that keep rolling through this late in the season I think we see a very similar water year like we did in 2011 which would be huge for Lake Powell water levels. I remember that year we kept getting snow storms in the mountains through June, much later than typical. That year the mountain passes here in Utah like Guardsman Pass and Mirror Lake Highway didn't open up until the 4th of July weekend. And even then the snow banks were still several feet high on the side of the road.

This year we had an above average snow year for most of the Upper Colorado River drainage, and it is still going. Our local forecast has rain/snow predicted for every day over the next week. The reservoirs above Lake Powell are already at 76% of capacity, Lake Powell has risen 10 feet this year so far, and we have yet to get to the warm temperatures needed to really bring down that snow. Once the temps finally warm up and stay there for about a week, I think we see some serious runoff. Unfortunately there might be quite a bit of flooding too.

UDOT typically tries to have the mountain passes open for Memorial Day weekend, but this year it's not happening. There is still about 4 feet of snow up around 9,000 feet and higher. I imagine Colorado is the same. This could end up being another banner year for Lake Powell lake levels. It's too bad last year was so historically bad.
 
Snowing on Monarch today. Temps have dropped 15 degrees her in Grand Junction which will slow the runoff. Already announced that Maroon Bells and Independence pass will not be opened by Memorial Day weekend. Numerous weddings had to be cancelled at Maroon Bells this spring as so many avalanches are going to take lots of time to clear.
 
drcalderwood said:
With the storms that keep rolling through this late in the season I think we see a very similar water year like we did in 2011 which would be huge for Lake Powell water levels. I remember that year we kept getting snow storms in the mountains through June, much later than typical. That year the mountain passes here in Utah like Guardsman Pass and Mirror Lake Highway didn't open up until the 4th of July weekend. And even then the snow banks were still several feet high on the side of the road.

This year we had an above average snow year for most of the Upper Colorado River drainage, and it is still going. Our local forecast has rain/snow predicted for every day over the next week. The reservoirs above Lake Powell are already at 76% of capacity, Lake Powell has risen 10 feet this year so far, and we have yet to get to the warm temperatures needed to really bring down that snow. Once the temps finally warm up and stay there for about a week, I think we see some serious runoff. Unfortunately there might be quite a bit of flooding too.

UDOT typically tries to have the mountain passes open for Memorial Day weekend, but this year it's not happening. There is still about 4 feet of snow up around 9,000 feet and higher. I imagine Colorado is the same. This could end up being another banner year for Lake Powell lake levels. It's too bad last year was so historically bad.
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Good analysis. I agree this year looks a lot like the pattern of 2011. That was a unique year because as you say, the lake kept rising, not hitting its peak until July 30. Put that in perspective--that's the latest peak in the lake's history. The year with the next latest peak was 1986 (July 27), 1967 (July 27), 1988 (July 25), and 1975 (July 25). More typical peaks are June 30-July 15. I'm guessing we're headed for a late peak again this year, for the reasons drcalderwood brings up...

This year the low point of the lake was almost the same date as in 2011--April 10 this year, April 9 in 2011.

In 2011, the lake added 5.9 MAF in volume until it hit its peak at the end of July. That is an incredible amount--about a quarter of the lake's total volume. The only years that exceeded that were 1973, 1979, 1993 and 1995, which ranged from an increase of 6.3-7.5 MAF. (The mid-80s would have seen similar or even higher numbers, except that the lake was already close to full before the runoff season started.) What that meant in 2011 was that the lake rose by 51 feet--from 3610 to 3661. The really big inflow didn't get going that year until early June, but from then until mid-July, the inflow stayed consistently between 73,000 and 85,000 cfs!! That's a much different pattern than most years, where the inflow begins to diminish by mid-June more like into the 30-40,000 cfs range.

What does this mean for 2019? If we added 5.9 MAF from April 10, we would peak at about 3630--a total rise of about 62 feet. Lake Powell has never seen a 62-foot rise in one spring. Close, but not that much (it was 58 in 1973 and 1979). That would be exciting. So far the pattern is much like in 2011. As of May 16, it's risen about 10 feet, compared to about 7 feet in 2011, but inflows are similar (25-30,000 cfs). In 2011, the inflows rose to close to 50,000 by the end of May, so I'd expect similar this year. Incredibly, releases were even higher in 2011 than this year, ranging from 15-25,000 cfs during the spring, compared to this year where were' holding at 12-13,000 cfs so far. So the potential for a big gain becomes even a little greater...

All very exciting, let's just see how this plays out....
 
JFRCalifornia said:
Good analysis. I agree this year looks a lot like the pattern of 2011. That was a unique year because as you say, the lake kept rising, not hitting its peak until July 30. Put that in perspective--that's the latest peak in the lake's history. The year with the next latest peak was 1986 (July 27), 1967 (July 27), 1988 (July 25), and 1975 (July 25). More typical peaks are June 30-July 15. I'm guessing we're headed for a late peak again this year, for the reasons drcalderwood brings up...

This year the low point of the lake was almost the same date as in 2011--April 10 this year, April 9 in 2011.

In 2011, the lake added 5.9 MAF in volume until it hit its peak at the end of July. That is an incredible amount--about a quarter of the lake's total volume. The only years that exceeded that were 1973, 1979, 1993 and 1995, which ranged from an increase of 6.3-7.5 MAF. (The mid-80s would have seen similar or even higher numbers, except that the lake was already close to full before the runoff season started.) What that meant in 2011 was that the lake rose by 51 feet--from 3610 to 3661. The really big inflow didn't get going that year until early June, but from then until mid-July, the inflow stayed consistently between 73,000 and 85,000 cfs!! That's a much different pattern than most years, where the inflow begins to diminish by mid-June more like into the 30-40,000 cfs range.

What does this mean for 2019? If we added 5.9 MAF from April 10, we would peak at about 3630--a total rise of about 62 feet. Lake Powell has never seen a 62-foot rise in one spring. Close, but not that much (it was 58 in 1973 and 1979). That would be exciting. So far the pattern is much like in 2011. As of May 16, it's risen about 10 feet, compared to about 7 feet in 2011, but inflows are similar (25-30,000 cfs). In 2011, the inflows rose to close to 50,000 by the end of May, so I'd expect similar this year. Incredibly, releases were even higher in 2011 than this year, ranging from 15-25,000 cfs during the spring, compared to this year where were' holding at 12-13,000 cfs so far. So the potential for a big gain becomes even a little greater...

All very exciting, let's just see how this plays out....
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An inspiring analysis, I LIKE IT 😁
 
Steve Moore said:
Snowing on Monarch today. Temps have dropped 15 degrees her in Grand Junction which will slow the runoff. Already announced that Maroon Bells and Independence pass will not be opened by Memorial Day weekend. Numerous weddings had to be cancelled at Maroon Bells this spring as so many avalanches are going to take lots of time to clear.
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It snowed enough on Monarch yesterday that the plows were out. We saw several inches at the top.

Sitting at Blue Mesa right now and there is a dusting of snow and it’s still coming down. I was hoping to go fishing.

I know we need the moisture but I’m ready for summer, or at least spring.

EABCC388-8666-4BE5-8EF1-B15831502A21.jpeg
 
Question - even though runoff has been delayed because of the cool wet weather, the SWE above LP has decreased from 21.5" to 12.5" - over a 40% decrease and has produced an 11' rise of the lake so far.

Yet we are still thinking an additional 30-40' rise will occur on only 12.5" SWE that is remaining?

(This is rough math, and I know there are variables such as filling upstream reservoirs, but I'm sure you get the point of my question)
 
Pegasus said:
Question - even though runoff has been delayed because of the cool wet weather, the SWE above LP has decreased from 21.5" to 12.5" - over a 40% decrease and has produced an 11' rise of the lake so far.

Yet we are still thinking an additional 30-40' rise will occur on only 12.5" SWE that is remaining?

(This is rough math, and I know there are variables such as filling upstream reservoirs, but I'm sure you get the point of my question)
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That's a really good point and good observation... not sure what all the factors are (not a hydrologist) that go into the math, but it seems to me that a lot of the melted snow is likely still far upstream of LP in the form of runoff, streamflow, or groundwater... and streams swell to much larger size (i.e., flow rate and volume) than non-spring flows... but your point is a good one... hmm...

And yet the data from past years similar to this one consistently show that inflow volumes (and lake rises) start really cranking up during the last week of May through the middle of June... the pattern is similar even in most years with lesser snowfall... In the years most similar to 2019 (all with minimums around April 10), here's what happened in April, May, June and July in terms of rise:

2005 (early peak 60-75,000 cfs in late May to early June)
April - 8 feet
May - 22 feet
June - 21 feet
July - 2 feet

2011 (late peak 70-87,000 cfs in mid-June)
April - 2 feet
May - 10 feet
June - 27 feet
July - 12 feet

2014 (peak 45-60,000 cfs in early to mid-June)
April - 4 feet
May - 10 feet
June - 21 feet
July - 1 foot

And of the three, the pattern of 2019--including April and early May flows--most closely match 2011... which also saw a 12-foot rise from April 10 to May 20...

...so far in 2019 it's a 3-foot rise in April, and 9 feet in May, with very similar daily inflow ranges as in 2011...and actually much lower outflows...
 
JFRCalifornia said:
Good analysis. I agree this year looks a lot like the pattern of 2011. That was a unique year because as you say, the lake kept rising, not hitting its peak until July 30. Put that in perspective--that's the latest peak in the lake's history. The year with the next latest peak was 1986 (July 27), 1967 (July 27), 1988 (July 25), and 1975 (July 25). More typical peaks are June 30-July 15. I'm guessing we're headed for a late peak again this year, for the reasons drcalderwood brings up...

This year the low point of the lake was almost the same date as in 2011--April 10 this year, April 9 in 2011.

In 2011, the lake added 5.9 MAF in volume until it hit its peak at the end of July. That is an incredible amount--about a quarter of the lake's total volume. The only years that exceeded that were 1973, 1979, 1993 and 1995, which ranged from an increase of 6.3-7.5 MAF. (The mid-80s would have seen similar or even higher numbers, except that the lake was already close to full before the runoff season started.) What that meant in 2011 was that the lake rose by 51 feet--from 3610 to 3661. The really big inflow didn't get going that year until early June, but from then until mid-July, the inflow stayed consistently between 73,000 and 85,000 cfs!! That's a much different pattern than most years, where the inflow begins to diminish by mid-June more like into the 30-40,000 cfs range.

What does this mean for 2019? If we added 5.9 MAF from April 10, we would peak at about 3630--a total rise of about 62 feet. Lake Powell has never seen a 62-foot rise in one spring. Close, but not that much (it was 58 in 1973 and 1979). That would be exciting. So far the pattern is much like in 2011. As of May 16, it's risen about 10 feet, compared to about 7 feet in 2011, but inflows are similar (25-30,000 cfs). In 2011, the inflows rose to close to 50,000 by the end of May, so I'd expect similar this year. Incredibly, releases were even higher in 2011 than this year, ranging from 15-25,000 cfs during the spring, compared to this year where were' holding at 12-13,000 cfs so far. So the potential for a big gain becomes even a little greater...

All very exciting, let's just see how this plays out....
Click to expand...
I live at the bass of Snowmass ski mountain, last night May 21 I skinned up to about 9400 feet at that elevation we had 14” of new heavy as hell snow. This should be a great runoff. It reminds me of 83, 84. The major difference is the lake is so low .
 
As Tim mentioned above we have so much snow and the run off in my opinion has not even begun here. We depend on run off for irrigation and it has not even started here. Initial low elevation run off sure but not above 9000' We are still skiing at Purgatory this weekend, first time ever to be open this late and its still snowing right now. Last year there was absolutely no snow on the mountain in fact the 416 wildfire started June 1... Crazy ! Been here since 1999 and never seen this. Snow pack was at 225% before these past 2 storms hit and another coming in on Memorial Day. I think it will be a historic run off and we will see rise rates like never before.
 
I was looking at that graph yesterday and I find it rather confusing as to the monthly flows versus cumlative flows. In the title it states the April through July flow of 9200 kaf (50% of probability range). The dotted line indicates accumulated inflow, I think. Only about 7200 accumulated through August. I don't think that is right. Dunno.
 
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Flow said:
@JFRCalifornia Am I reading this projection chart right?

https://www.cbrfc.noaa.gov/wsup/graph/front/espplot_dg.html?year=2019&id=GLDA3

To me, it looks like we are on track as of 5/15 to have a peak inflow from April-July of over 6 MAF and ending with a total inflow of 7.2MAF in August, is that right? I may have read it wrong
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Well I'm not entirely sure I can interpret this data correctly either, but it's very cool stuff for sure! The way I read it, there's a 50% probability that total accumulated streamflow will end up exceeding 9.2 MAF, whereas normal by August is 7.2 MAF... and that total accumulated so far is at about 2.85 MAF, which is on track to be normal... however, jump back to the 2011 data and you'll see what happened that year--it went off the charts after being "normal until the end of May, and in mid-June and was at 11.5 MAF accumulation in mid-July, compared to expected normal of 6.8 MAF at that point... but it also shows we're not quite at the same volume potential this year as in 2011, but not too bad...

By the way, look at the 2018 graphs if you want to see something awful...

Bottom line is that I'm not sure what I'm talking about, but I like to talk...
 
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Pegasus said:
Question - even though runoff has been delayed because of the cool wet weather, the SWE above LP has decreased from 21.5" to 12.5" - over a 40% decrease and has produced an 11' rise of the lake so far.

Yet we are still thinking an additional 30-40' rise will occur on only 12.5" SWE that is remaining?

(This is rough math, and I know there are variables such as filling upstream reservoirs, but I'm sure you get the point of my question)
Click to expand...

I am not sure what data you are looking at, but the water year resets on the reports I am accessing around April. This is important because what you might be looking at is 12.5" of water since the start of the new water year and not a decrease in the SWE. The actual SWE that is present on the mountain could be much higher than 12.5"...
 
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