Pamela J. Bennett and Jane C. Martin
The growing season of 1999 was a season of drought in Ohio. In February, precipitation indications for the calendar year were off to a good start as far as water supplies were concerned, but by the end of March, most regions of the state were rated at incipient to mild drought. By June, all of the state was in moderate to severe drought.
Rainfall in July improved drought ratings, but by the end of September, most regions of the state were still rated in moderate to severe drought, with the southwestern and south-central regions rated as extreme. Ratings are based on the Palmer Drought Severity Index; for a discussion of this index, see the section following Weather Background in this report.
The year began with a wetter than normal January, February, and April across the state. However, March, May, and June were well below normal in precipitation. In addition to scant precipitation, temperatures soared above normal in May, June, and July, which affected planting and establishing ornamental plants. Lawns were going dormant as early as mid-June in some locations.
Despite the regional reports of drought, some locations in the state escaped the intensity of drought that occurred in other locations.
Temperatures in much of Ohio were summer-like as early as May. Temperatures soared in July, with many locations reporting numerous days over 90°F and heat indices soaring into the 100s. Heat-related deaths occurred in the Cincinnati area. An overview of the state’s weather conditions for January through September is presented in the following report.
This report includes a compilation of Ohio weather conditions and noteworthy environmentally induced and cultural plant problems in 1999. Observations were drawn from information provided in Ohio State University’s Buckeye Yard and Garden Line, the Ohio Department of Natural Resources Monthly Water Inventory Report, and information from the State Climatologists’s Office for Ohio.
Weather Background
This section discusses precipitation and temperature reports for the season. At the end of this section is a table of statewide precipitation from January through September, and average temperatures and departures from normal for three locations in the state, April through September.
Precipitation in January was above normal statewide, with only a few locations below normal. Snow and wintery mixes of rain and snow fell the first half of the month, with rain the second half. Snowfall was above normal during the first three weeks, with below normal temperatures. School closings and travel problems arose in many locations.
Precipitation in February was above normal in Ohio, with rain the first half, and snow the second half of the month. Snowfall was below normal for February. By the end of February, forecasters were predicting that the calendar year was off to a good start as far as water supplies were concerned.
Precipitation in March was below normal. This was the 19th driest March in 117 years of weather records. By the end of the month, forecasters were saying that precipitation so far in the year was not especially good for ground-water supplies.
April produced above normal rainfall with storms and thunderstorms in most of Ohio, though it was below normal in southern Ohio. May precipitation was noticeably below normal, with only light and spotty showers, making it the 18th driest May in 117 years. Weather in May was summer-like with temperatures soaring into the mid-80s.
June rainfall was also noticeably below normal, and it became the ninth driest June in 117 years. Springfield was already reporting a shortage of 7.6" of precipitation for the year, and Painesville was at -6.0". With the lack of rainfall came higher than normal temperatures that soared into the high 80°Fs and low 90°Fs. For instance, Cleveland recorded 90°F on June 10 and Columbus recorded 96°F, while Cincinnati recorded 94°F on June 8.
July precipitation was above normal in the northern half of Ohio, but below normal in the southern half. High temperatures and dry conditions intensified drought conditions. Intense heat occurred in July, with several heat-related deaths in the Cincinnati area. Cleveland reported 10 days over 90 degrees, with the high being 95°F. Columbus had 20 days over 90 degrees, with a record high of 100°F on July 31. Cincinnati had 17 days over 90°F, with 101°F on July 30. The Akron-Canton area reported 14 days over 90°F. Lawrence County reported 26 days over 90°F, with a high of 101°F on July 31.
At the request of Governor Bob Taft, U.S. Department of Agriculture Secretary Dan Glickman declared 66 Ohio counties as agricultural disaster areas. This was requested based on anticipated and existing economic hardships in the agricultural community as a result of drought-related stress to crops and livestock.
August precipitation was below normal except in the northwestern region, which was slightly above normal. By then the 1999 precipitation calendar year was well below normal. Interestingly, although drought conditions continued to worsen across the state, water supplies remained adequate. However, both voluntary and mandatory water-use restrictions were imposed in many areas. Fortunately, temperatures moderated in the first week of August to the 80°F range.
September remained dry statewide except for the northeastern region, which received 119% of normal rainfall. Precipitation for the 1999 calendar year was below normal statewide, recording the seventh driest May-September growing season. Average rainfall was only 13.24", which was 4.87" below normal. Locally, rainfall deficits added up. At the end of September, these areas were reporting calendar year shortages of precipitation – Cincinnati, -7.0"; Columbus, -9.1"; Springfield -11.0".
At the end of September, every region in Ohio was still in drought condition. One region was rated as mild, four were moderate, two were severe, and three were extreme.
1999 Statewide Precipitation, January Through September |
||
|---|---|---|
| Month | AverageInches Precipitation | Percent of Normal |
| January |
4.28
|
155
|
| February |
2.59
|
116
|
| March |
1.97
|
58
|
| April |
4.19
|
119
|
| May |
2.27
|
60
|
| June |
2.07
|
52
|
| July |
3.81
|
97
|
| August |
3.15
|
91
|
| September |
1.94
|
65
|
| Data from Ohio Department of Natural Resources, Monthly Water Inventory Reports. | ||
The National Weather Service provides a valuable analysis of moisture by using the Palmer Drought Severity Index (PDSI). The index is calculated by using precipitation totals, average temperatures, water capacities of the soil, and previous history of indices. These calculations provide a number for specific geographical areas that reflects overall moisture conditions. When placed on the PDSI scale, these numbers provide a relative method for assessing moisture conditions and for comparing conditions among regions.
The scale ranges from below -4.0, which is the Extreme Drought category, to above +4.0, which is the Extreme Moist Spell category. Near Normal is considered 0.4 to -0.4.
The drought and its effect on plants were frequent topics of discussion on the Buckeye Yard and Garden Line conference call. A summary of these discussions follows.
Fantastic Fruits
It was suspected that the combination of a lack of early spring frosts and low disease pressures in the spring and early summer led to many fantastic fruit displays. For example, Erik Draper and Jim Chatfield noted that one particular taxa in their crabapple evaluation plots normally had received very low aesthetic ratings due to scabby fruits. ‘White Cascade’ is normally defoliated and fruits ruined due to crabapple scab. However, this season, with the low incidence of scab, the fruits were very attractive. Many observers also noted that various dogwoods and viburnums had more numerous and showier fruits this season.
Water Needs
By fall, the word "critical" was used quite often when referring to water needs of plants. By early September, many trees, shrubs, and evergreens were showing drought injury, either in the browning or loss of leaves and needles. Observers noted that newly or recently planted materials failed due to lack of water. Recommendations to central and southern Ohioans to thoroughly water woody plants and perennials were common.
Various watering techniques were suggested, but the consensus was to water slowly and thoroughly, paying special attention to conifers and broadleaved evergreens. In addition, it was stressed to check for penetration of water, particularly if mulch was on top of the soil. Some forms of mulch, as they decay, became hydrophobic and prevent water from penetrating to the root system.
Average Temperatures and Departures from Normal, April through September |
||||||
|---|---|---|---|---|---|---|
| Cleveland | Columbus | Cincinnati | ||||
| Month | Avg. Temp F°^ |
Departure F° |
Avg. Temp F°^ |
Departure F° |
Avg. Temp F°^ |
Departure F° |
| April | 50.4 | +2.8 | 55.0 | +4.0 | 55.0 | +1.8 |
| May | 60.2 | +2.6 | 64.8 | +3.6 | 63.5 | +0.6 |
| June | 70.1 | +2.5 | 74.5 | +5.3 | 73.0 | +2.0 |
| July | 76.2 | +4.3 | 80.2 | +7.0 | 79.0 | +3.9 |
| August | 69.1 | -1.3 | 73.0 | +1.5 | 72.7 | -0.8 |
| September | 65.0 | +1.1 | 67.8 | +2.3 | 66.8 | -0.8 |
| ^ Average
temperature is an average of all high and low temperatures recorded daily
for the given location. Data for Cleveland was taken from http://www.csuohio.edu/nws/climate/cle/climatecle.html. Data for Columbus and Cincinnati was taken from http://www.nws.noaa.gov/er/iln/lcdpage.html. |
||||||
Discussion also focused on overwatering as many gardeners were unknowingly applying too much water in order to get plants through the drought. It was recommended to keep a record of irrigation amounts and dates. In addition, it was stressed that people check the soil with a probe to determine depth of moisture.
Water should be applied adequately once every four or five days, or weekly, depending on air temperatures. Soil should be soaked so that it is wet to a depth of at least six inches or to the depth of the root balls in the case of newly planted trees and shrubs. Mulch will help hold in soil moisture for a prolonged period. For herbaceous ornamentals, it was recommended to water in the morning and keep water off of foliage, if at all possible.
Disease Incidence
Overall, the incidence of disease problems, such as anthracnose diseases, apple scab, rose black spot, Guignardia leaf blotch of Aesculus, and many other foliar diseases, appeared to be lower this season.
Lightning and Trees
Ohio experienced the usual pop-up thunderstorms during the summer which prompted concern about lightning damage to trees. The July 29 issue of the Buckeye Yard and Garden Line included the following article on lightning damage to trees:
"With recent pop-up thunderstorms crossing Ohio, tall trees have become targets for lightning strikes. When a tree is struck, the owner is usually distraught at the thought of losing it. The nature and extent of lightning damage to a tree can vary enormously. Branches and trunks can be blown apart or split open, crowns killed, or large limbs broken out. In hardwood trees, a continuous groove of bark and/or wood can be stripped from the entire length of the trunk and main branches. In other cases, xylem can be injured without any external evidence, or part or all of the root system can be injured or killed. It is believed that variations in injury are related to lightning intensity, tree species, amount of water in the bark, and the character of branch and trunk tissues.
"Lightning most likely strikes lone trees, tall trees, and trees growing in moist soil or near bodies of water. Deep-rooted or decaying trees appear to be hit more than shallow-rooted or healthy trees.
"Many trees that are struck must be removed, while others may be worth attempts to save. Since the extent of internal damage can’t be assessed immediately, repairs should be limited to safety pruning and cleanup until survival seems assured. Carefully trim away all loose bark back to the area where it is solidly attached, using a sharp knife or chisel. Do not cut too deeply into the wood of the tree. Trimming the bark in this manner will encourage rapid healing with minimal wood decay. Stimulate root growth to improve water and nutrient movement to the top, by applying fertilizer under the drip zone and watering it in. After a full growing season, assess the tree’s health, and do more careful pruning and wound repair. However, struck trees may continue to fail over a period of years, eventually requiring removal. Although trees can be protected with lightning rods, they will become more prone to strikes. However, a properly installed system will protect the tree."
http://www.dnr.state.oh.us/odnr/water/pubs/newsltrs/mwirmain.html