Here are the top ten things you may or may not have heard of........regarding our local weather & climate.
1. Different Types of Severe Weather Peaks at Different Times of Year In Our Area.
Overall in the viewing area tornado occurrence peaks in late May to early June, but the occurrence of violent tornadoes peaks earlier.....in mid to late April when looking data 1870-present.
Hail occurrence tends to peak in early to mid April, but the peak size occurs in mid to late May.
Damaging straight-line wind occurrence peaks in mid to late June.
In terms of peak rainfall for the year, it peaks in late June to mid July in the far north, late May to early June in the central & south & mid May in the far southern parts of the area.
2. Evidence of Significant, Very Large, Pre 1500s, +1-Mile Wide Tornado Was Found In Montgomery County In the 1880s.
I thought putting the actual account of this from the author would be best!
Here it is:
BY JNO. T. CAMPBELL.
Last April (1885) I was surveying in the west-central part of Parke county, Indiana. On the south side of Section 16, Township 15 north, of Range 3 west, I noticed that the tree graves were very numerous, there being one to every square rod of ground. I noticed that they all indicated that the storm which caused them was going to the north-east. When a tree is blown down the roots hold two to five cubic yards of earth in their grasp, which makes a corresponding pit where the tree stood; after the fallen tree has entirely rotted, the earth held by the roots leaves a mound resembling an old grave, and have been very commonly called by people here, "Indian graves." The mound is always on the side of the pit toward which the tree fell.
This storm track was about one thousand feet wide. I at that time followed it nearly one mile. Just before I ceased tracing it I found the stump of a white oak, cut down during the year 1884, standing on top of one of the tree graves or mounds. I counted the rings of growth and found it to have been two hundred and ninety-seven (297) years old. That settled the fact that the storm passed over the ground at least three hundred and ten years before; for the acorn could not sprout on the mound until the tree had first been blown down; and second, it could not sprout until the fallen tree had also rotted away, and left the mound sufficiently flattened for moisture to rise to its top surface.
On the 18th of May following I was surveying in Section 29 and 30, Township 15 north, of Range 8 west (which surveyors in the west will understand is about three miles to the southwest of the first place mentioned). Here I also found the tree graves as thick as the grown trees now are, and they also indicated that the storm which blew down the trees which made these tree graves was going north-east. A moment's reflection also showed me that this was on the same line or track of the first one observed.
After I returned home I placed a string on my county map so as to cover these two locations, and noted carefully what points across the county the string touched. I noticed that by extending the string south-westward it passed about one-half to three quarters of a mile to the right of Clinton, in the south end of Vermillion county which adjoins this county on the west, the Wabash river lying between them. Clinton stands on the west bank of this river. I at once remember as a boy in my early "teens" I had lived with a Dr. Kile, two and a half miles of Clinton, and in my frequent trips to town I often noticed the tree graves, which in my simplicity then I supposed them to be in fact real "Injun graves." They were very numerous and I supposed there had been a great battle between two hostile tribes of Indians, and that these mounds were the graves of the unknown braves. There were not the very faintest trace of fallen trees in connection with these graves, so thoroughly had they rotted away. I found by applying the string to the map that these graves were in line with those I had recently found in this (Parke) county.
On the 8th of July following (1885) I was making a survey in the northeast part of the county, in Section 29, township 17 north, of range 6 west. While at the dinner table I was told by one of the land proprietors that I had recently got upon the track of an ancient storm which, if it had kept on the course I had observed should pass on the ground we were then eating our dinner on. I asked him if he had ever noticed any trace of it. He said, "Yes. When I was a boy and a young man the 'Indian graves' out in the field (pointing south-eastward) were so thick that I could jump from one to another all over that part of the farm." I asked what course the storm was going, and explained how he would know by the position of the mound in relation to the pit. He said north-east, and told me what farms it crossed, and about where it crossed the county boundary into Montgomery county, which was close by. This was over fifteen miles from where I had first discovered the track, and I had not missed its location from where I am now speaking about more than seven hundred feet.
The next day I was going to another part of the county, and had to travel south-westward several miles, and crossed the storm track. I saw a man in the edge of a field harvesting. I told him what I had discovered, and asked him if he had ever noticed it. He answered, "Yes. When I was a boy the Indian ('Injun') just below that sugar camp [grove of sugar maples] were as thick as stumps in a new clearing. We boys used to count them to see how many Indians had been killed in battle." It was the general belief of the children of the early settlers that these were Indian graves, and that where they were numerous, as in a storm track, that there had been a battle between tribes. The place where he pointed out was in the track I was looking after.
I may here remark that after the land is cleared and cultivated, the plow in a very few years destroyed all trace of these graves.
This storm would pass, in going north-east, about two miles to the left of Crawfordsville, Indiana, the county seat of Montgomery county. Though it might change its course farther on.
At, or very near the spot where I counted the age of the oak which had grown on one of these tree graves, there still stands on another mound a white oak considerably larger than the one I counted, though it may not be an older one. I have delayed writing this account over six months, expected a miller to cut this larger tree so I could count its age, but it has been neglected so long that I have decided to write from what information I now have.
These tree graves are, in the wild forest, as well preserved and as distinct in outline, although more than three hundred years old, as many that have been made by trees that have fallen within my own recollection. If the same conditions that have so well preserved them for that time should continue in the long future, I see no reason why these mounds might not be preserved five thousand, yea, ten thousand years.
Why does the reader guess has so well preserved these little mounds for so long a time? It is nothing more nor less than a thin coating of forest leaves. The leaves act as shingles in shedding the rains, so that they are not washed or worn down by the falling rain or melting snow. The frost does not penetrate through a good coating of leaves, and therefore they are not expanded and spread out by freezing and thawing. I can see a great difference between the mounds in the wild forest and those on land that has been set to grass and pastured a few years. The tramping of stock and frequent expansions of freezing, which the grass does not prevent, flattens them perceptibly. The grass, however, does preserve them against rain washings. When a belt of forest is blown down, there are no leaves to produce leaf shingling till a new set are produced; but these come in great abundance in ten years. It requires about fifteen to twenty years to rot a sound white oak. The time will depend on the lay of the log, whether it falls across another log and lies above ground, or lies on or is partly bedded in the ground.
I now offer a conundrum in connection with this subject for whomsoever may feel an interest in it to solve. I have partly solved it myself, but not entirely to my satisfaction. I have, after much observation, noticed that not more than one-tenth of the present forests show any trace whatever of any storms, recent or ancient. If storms have been as frequent and destructive as in the past as in my day (of fifty three years), and the elements of preservation of the mounds have existed as the past as now, why do I find so few storm tracks as I have mentioned? It would seem in three hundred years, if storms have always been as frequent as in our time, and in the same haphazard manner, there would not be a square rod of ground that would not show some trace of a storm.
I give my explanation for what it may be worth, but is short of all the facts of explanation. I am able to say of the storm I have described, with as much confidence as I have had been present and seen it; first, that it occurred when the trees were in full leaf; second, that there had been a protracted rain; third, that many of the trees that were blown down were white oak; fourth, that one was a large poplar; fifth, that few, if any at all, were black walnut. And for the following reasons: The great storms do not now occur before the leaves are on. Without the resistance against the wind offered by the leaves, it is very hard for a storm to uproot a green tree. If the ground is dry and hard, or frozen, the trees will break off at or above ground. And in such case they would leave no tree graves, which may account for the few tracks I find. An oak leaves a deep, round pit and a plump, round mound. A poplar leaves a broad, shallow pit and a long, slender mound. The black walnut is very rarely "blown up by the root." I have seen this country from an unbroken forest to the present time, when four-fifths of the land is cleared for the plow or pasture, and I don't remember that I ever saw a black walnut blown up by the root. I have seen many broken off. They have a very firm tap root, and are, when mature, a little doughty at the stump, but very sound from ten feet above ground upward.
I have seen and still know of other large trees which stand on the graves of former fallen trees. Some of these trees are very large, but the size of a tree is such an incertain indication of its age, that I can't say with much certainty how long the mounds on which they stand have existed. One thing is certain, the mounds are older than the trees. At the fair ground, a mile west of where I am writing (Rockville, Indiana) are several such cases, and on the grounds of the now growing famous resort in our county, "Turkey run," or as it is called by people away from here, "Bloomingdale glens," are several such cases.
In a future article I shall show how the forest leaves have preserved the sides of hills and thus allowed the small streams to cut out the bottoms of the hollows deep, steep and sharp, which are rapidly changing since the country has been cleared and farmed. Also how they have preserved the ancient beds of streams along the terrace bottoms of the Wabash river and its principal tributaries till they are as sharply defined after the lapse of no one can venture to guess how many thousands of years, as they were when the last great final flood that cut out the beds swept over these plains.
I have said the storm here described was a cyclone. This I infer from the way the trees had fallen. In some parts of the track, the trees were thrown in every direction, and the course of the storm could only be determined by the general course of the track, and not by the fall of individual trees.
The course of the storm is N. 44° 30' E. in this county. In all my recollection of storms I never saw but one (in 1883) which bore so much to the north, and that one was the most threatening and awful in its appearance I ever saw, and did in localities much damage. Its course was N. 37° E., or about 7° 30' more north than the ancient one. The great majority of the storms I have seen, and of those which have left plain tracks, are from a few degrees north to a few degrees south of west.
Track of a Cyclone which Passed Over Western Indiana more than Three Hundred Years Ago By Jno. T. Campbell The American Naturalist , Vol. 20, No. 4 (Apr., 1886) , pp. 348-353 The University of Chicago Press for The American Society of Naturalists
3. Tippecanoe County Averages More Tornadoes Per Square Mile Than Any Other County In Our Area.
This belt of enhanced tornadic activity also extends into Benton & northeastward to White County. This climate zone change is often a belt where warm fronts stall in spring & fall, resulting in enhanced shear & tornadic activity. This is based on records 1880-present.
4. A Mega Flood Occurred At the End of the Last Ice Age
Lake Erie use to go all the way to Fort Wayne at the end of the last Ice Age +10,000 years ago. A natural dam gave way as it filled with a massive amount of glacial meltwater & burst, sending an apocalyptic wall of water down the Wabash. An incredible erosive force, the rugged, deeply eroded, scenic topography we see around West Lafayette, Lafayette, along Old State Road 25 in Carroll County, around Logansport, even the cliffs & ravines in Fountain County & the carved cliffs along Sugar Creek, were all caused by a combination of this mega flood & melting glaciers overall. Called the "Maumee Torrent", it was one of the great geological events in Indiana prehistory & fundamentally caused by a rapidly-changing climate at the time.
The same eco-region that occurs around Turkey Run State Park & Shades also occurs right up the Wabash through Williamsport to West Lafayette (Happy Hollow Park is a good example), Lafayette to Battle Ground (Prophets Rock, etc.), through Delphi to the bedrock bottom Wabash at Logansport. The rugged, wooded terrain Peru to Huntington is part of the same eco-region, as well. Several plants more typical of the Northern & Northeastern United States & southern Canada are found in the deep, deep moist, dark, cool ravines of the deep forests of this eco-region, a far cry from the prairie, barrens, savannas & oak-hickory woodlands that are more typical & usually occur nearby.
5. Mega Droughts Have Occurred In the Past
Ancient, knarled Eastern Redcedars & Blackjack & Post Oaks on cliffs along the Mississippi, Ohio Rivers & in southern Illinois show evidence of Medieval Mega Droughts that lasted for a decade or more, even in this region. They seemed to peak between 650 & 900 A.D., according to reconstructions by Columbia University. Considerable charcoal in sediment shows evidence of widespread fires (Native American & lightning-induced) & a wave of significant prairie expansion after some decrease after the main "Prairie Period" of 4000-8000 years ago. Many Plains & sandy coastal plain species migrated into the area that only exist as small, isolated relict populations in our area today (like small tidal pools once the tide has receded).
In the 1500s, multiple, major droughts like 1936 occurred for up to a decade.
6. The number of +95 & 100 days has been decreasing in our area since the 1950s.
Occurrences of upper 90s & temperatures exceeding 100 for multiple periods in summer has been on the decline. Since 1955, only four years at West Lafayette have hit or exceeded 100 officially. Since '55 24 years have reached or exceeded 95 degrees.
From 1880-1954, 29 years reached or exceeded 100 degrees. In the remaining years only 9 of those years failed to reach 95 or more!
Drought occurrence & severity has also been on the decline since the late 1980s. 2011 & 2012 is the exception.
Climate is very cyclical with pluvial (wet) & dry periods, but the exact reasons for this +95 & 100s downturn are a bit unclear. An increase in dew points has been noted since the 1950s. It could very well be that corn populations are much thicker now (number of plants per acre) & the fact that they produce so much yield, they may transpire (release more vapor in the air) more now. This may have a factor in altering our micro & meso climate by adding much more moisture to the air, which lowers the air temperature a hair. Nightly lows have trended a bit warmer than decades ago, so this seems to make some sense.
However, even with all of the water around in marshes & swamps, extensive prairie & forests before European settlement, drought was still MORE prevalent, according to sediment cores & tree rings.
Also of note, is a bit of a change since the 1800s to 1930s from our highest temperature of the year more likely now to occur either very early in the season or later in the season.
7. Prehistoric dust storms struck the area.
The sand dunes & blanket sands we find in parts of our area like Newton, Jasper, Pulaski, Fulton, Cass, White, Tippecanoe & Fountain counties are all wind-blown deposits (there is some water-deposited sand & gravel in outwash, kames & eskers, too).
As glaciers receded (as the climate warmed) & filled valleys & bottomlands with tremendous sand, silt & gravel, these bare areas, nearly, if not, devoid of vegetation had very little to hold soil in place. As the water receded from freezing in the winter that stopped melting or after all ice melted & water receded, strong west to southwesterly to northwesterly wind gradient funneled in the wind that led to the great dust storms. There is also evidence of strong east winds, too, at times. This may have been the result of high pressure over ice sheets to the north & lower pressure south of the sheets that brought the east winds.
Think what would happen if every single county & every amount of space north of interstate 70 was plowed & had much of its vegetation taken away. Imagine the blowing dust during the winter (when the ground froze) & spring (when the ground dried)!
In fact, the dust storms were so extensive (& likely darkened the skies), a good chunk of Indiana is mantled or blanketed in wind-blown floury soil called loess. It is thickest east of sand dune belts adjacent to glacial lake plains & large outwash plains, carved by by melting glaciers. Sand is a heavier soil particle so you find dune deposits in less extensive areas of the state.
8. Frost has been reported every month (even June, July & August).
The earliest patchy frost on record at West Lafayette (since 1879) occurred August 29, 1965. July patchy frost in the area has been reported by early records in 1816, 1842 & then in the far northern parts of the area in 1863. These reports came from early pioneers in Tippecanoe, Carroll, Cass & Jasper counties.
June patchy frost has been reported as recently as 1992 & 2003.
9. There is a very distinct climate zone change from White to Tippecanoe counties.
Looking at the climatology of storms, snowfall, frost/freezing, drought, phenology (when plants bud & bloom in spring....birds return) & winds, once you drive north of Brookston, the climate is much more like the Chicago area. South of there, including Greater Lafayette, the climate is much more like Indianapolis & the rest of central Indiana.
10. West Lafayette has never had a year since record-keeping commenced that it has not hit 90 at least once.
1883, 1958, 1979 & 1993 are noteworthy in the lack of 90-degree days with generally only 1-2.