Monthly Archives: May 2011

Snowy Springs

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Today is the last day of meteorological spring.  A year ago we were finishing up the first spring on record with no measurable snowfall recorded.  That was in stark contrast to the previous two years of 2009 and 2008 when we recorded the 3rd and 4th highest spring snowfalls on record.  Both of those years brought nearly 30 inches of snow from March 1 through May 31.

After a one year hiatus from the onslaught of spring snow, this year once again turned snowy.  The past three months the official observer in north Moorhead measured 21.5 inches of snow.  That was enough to rank the spring of 2011 as the 12th snowiest on record.  Including this year, 5 out of the top 12 snowiest springs have occurred since our current wet cycle began in the early 1990s.

This has coincided with an overall cooling of our spring seasons that has been combined with above average precipitation, therefore, higher snowfall amounts have not been surprising.

Dry to Wet

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My career as the meteorologist on WDAY began a little more than 26 years ago in May of 1985.  The 1980s were dry years.  Spring brought dust storms whenever an afternoon turned hot and windy.  The day I moved to Fargo, dust hung over the Red River Valley like a brownish-yellow haze.

It was not unusual for there to be several days in April and May with temperatures soaring into the 90s.  Lawns would turn green in mid spring but would quickly begin to brown.  The 1980s were not as dry a decade as the 1930s had been, but crops were getting by only with timely rains while rivers ran low and slow.  Lake home owners were adding to their docks in order to reach the water.

Lake Sakakawea was shrinking while the people of Devils Lake were looking for funding to build a pipeline to bring water from the Sheyenne River in order to raise the level of the lake.

My but how things have changed!

First Day of Summer Vacation

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The weather this week has really put a chill on the spring spirit.  As spring setback go, we expect the March blizzard and the late April snow, but by May we begin to feel that we are owed some good weather.  Certainly Fargo public school kids expect more from their first day of ?summer?. (That Fargo public schools start too early in the fall and end too early in the spring is an argument for another day.)

But this sort of thing happens from time to time around here in May and even in June.  The culprit is a flow of air from Hudson Bay.  In winter, our coldest air usually comes from the Yukon or the Northwest Territories or even from Siberia over the pole.

But in late spring, some of the coldest weather in the northern hemisphere can usually be found over Hudson Bay, and when there is a north to northeast breeze stiff and steady enough to bring that air this way, the result is a week like this one; very disappointing and un-spring-like.

Wet, Wet, Wet

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As the spring of 2011 wanes, the state of North Dakota is almost completely saturated.  From the Red River in the east to the Little Missouri in the west, rivers are overflowing their banks.  From Devils Lake to Lake Sakakawea to almost every pothole in between, water is at record levels.

Grasslands have become wetlands.  Wetlands have become sloughs.  Sloughs have become large lakes.  And Devils Lake, the North Dakota wet cycle poster child, is now a vast inland sea.  Many have speculated, but no one knows when this pattern of high precipitation will tapir.

But there is a clue in a very old farmer?s proverb from England.  ?There is no debt so surely met as wet to dry and dry to wet.?  Although it is hard to imagine today, there will come a time when it will be too dry across North Dakota and we will all be wishing for a nice, soaking rain.

A Bad Year

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In many different statistical categories, 2011 is turning into one of the worst years on record for tornadoes.  April set the record for the most tornadoes with 875 reported across the nation.  Tornado numbers in May are still preliminary, but the national total for 2011 so far is already approaching the three-year average over an entire year and it isn?t even June yet.  There have been an unusual number of large and violent tornadoes and several have hit large population centers including Tuscaloosa, Birmingham, and Joplin, resulting in some 500 deaths so far this year.

But before jumping to the conclusion that we now live in a new and terrible tornado regime, consider that tornado activity had been below average for several years in a row.  Consider also that, historically, there have been years with high tornado statistics from time to time.  Much like the wild hurricane season back in 2005, the U.S. is having a really bad time with tornadoes this year.

But it is likely just a bad year and not a foreboding change.

The Possible Reality

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When I was in graduate school, one of the tornado disaster scenarios that was frequently mentioned was a F4 or F5 tornado moving through the Dallas/Fort Worth area during rush hour.  With tens of thousands of individuals in grid-lock on the freeways with no shelter available, it was theorized that hundreds of individuals could die in such an event.

At the time it opened my eyes to the possibility of a mega-tornado disaster in an urban setting.  If memory serves, a made for TV movie or documentary of such a scenario was made a few years later.  Then, on May 3, 1999 a large tornado ripped through portions of Oklahoma City clearly demonstrating that such a disaster was more likely than many imagined.

Large tornadoes are always rare, plus the odds of one striking a densely populated area is always low, but this tornado season has sadly reminded us that as urban centers expand, so do the odds of additional tragedies occurring in the future.

100 inches

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In a previous blog posting, I wrote about how our 30 year average rainfall in Fargo Moorhead is currently 22.75 inches up from the previous average of 21.19 inches.  This new average is based on the years from 1981 through 2010.  It is important to remember, that the 1980s were generally dry with an average rainfall of only 18.64 inches, but the 1990s and 2000s the average increased by 6 inches per year with an average of 24.80 inches.  Therefore, the current 30 year average does not reflect just how much additional rain has fallen in the area in the past 20 years.

In my numerous public talks on the recent flooding and wet cycle, I emphasize the simple fact that in the past 20 years, Fargo Moorhead has received over 100 additional inches of rain when compared to what fell during other such periods in the 20th century.  Plus, many other locations have been even wetter.

It is no wonder flooding has been so frequent in the past decade.

Mountain Snow in ND

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The Red River is not the only river basin with water problems this year.  The level of Lake Sakakawea, in western North Dakota, is very high due to two years of heavy winter snow and summer rainfall.  This winter, the snow pack in the Rocky Mountains around Yellowstone National Park is 125 to 150 per cent of normal.  This amounts to two to three feet of water content which will be melting and running through the Missouri and Yellowstone Rivers and into Lake Sakakawea during June.

In anticipation of very high water levels, the Army Corp. of Engineers is presently releasing water from Garrison Dam at a very high rate, resulting very high water levels downstream.  A number of boat ramps in the Bismarck area are now closed due to the high water. And things have the potential to get worse in June with the introduction of all the water from the Rockies.

Weather Stats

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Mark Twain once said, ?There are three kinds of lies; lies, damn lies, and statistics.?  Politicians and those who follow politics are well aware of how one particular statistic can be made to say different things by different people.  Weather statistics can be just as misleading or as confusing.

For example, on an earlier blog writing in this space, Daryl Ritchison wrote that the average first 80 degree day in Fargo Moorhead is May 6.  Well, today I am telling you that the average high temperature does not reach 80 degrees until June 26.  These two statements appear to be in conflict, yet both are correct.  The difference is subtle but quite important.  The first statement refers to the first date in the spring when, on average, the weather warms to 80.

This usually happens well before the average daily high is 80 degrees, which is the subject of the second statement.  Understand?  Mark Twain certainly did.

Getting Wetter

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When referencing climate normals, this refers to the average of a given weather variable during the previous 30 years of record keeping.  To eliminate the frequent changing of these normals every year, the averages are based on the previous three full decades.  Therefore, until this year, our climatic normals were based on the period from 1971 through 2000.

Since January 1, 2011, our averages are based on the period from 1981 through 2010.  These new climate statistics which are still being calculated will stay the same until January 1, 2021 when the new climate statistics for all locations will be based on the period from 1991 through 2020.  The first 30 years of record keeping in Fargo Moorhead was from 1881 until 1910 when our average rainfall was 24.40 inches and then average rainfall locally declined until around 1960 when our average was 18.45 inches.

Our current wet cycle has cause a rapid increase in our average annual rainfall which is currently 22.75 inches, the highest since that first 30 year average in 1910.