Great Lakes quarterly climate impacts and outlook: September 2014

September 2014

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Great Lakes Significant Events - for June - August 2014

Summer 2014 was cooler than normal across the Great Lakes basin, with basin temperatures 1°C (1.8°F) to 3°C (5.4°F) below normal in July and August. In fact, 5 of the 8 U.S. Great Lakes states ranked July 2014 among their top 11 coldest Julys on record.

Wet conditions continued to dominate across the Great Lakes basin resulting in water levels rising more than usual for this time of year on each of the lakes, except Lake Ontario where above average outflows offset wet conditions. Lake Superior ended the quarter above-average and at levels not seen since 1996. Lake Michigan-Huron levels began September just below its long-term monthly average and at levels not experienced since 1998.

A "harmful algal bloom" developed in Lake Erie this summer, with wet weather and agriculture fertilizers the suspected drivers. Harmful algal blooms are any large increased density of algae with significant socioeconomic or ecological effects including toxins, beach fouling, intake clogging, reduced property value, and/or taste-odor issues.

Flooding was a major issue this summer across the Great Lakes basin. In mid-August, Detroit, MI and Windsor, ON both experienced significant flooding after intense, heavy rainfall. In Detroit, 102 mm (4 in) to 152 mm (6 in) of rain fell within 8 hours on August 11, much of which fell during evening rush hour. In Windsor, the 74 mm (2.9 in) of rain that fell on August 11 was their second wettest August day on record. On August 4, significant flooding of highways, streets, and a few thousand homes occurred in Burlington, ON, when up to 190 mm (7.5 in) fell locally within a few hours. Several communities within MN also felt the impacts of flooding in late June. In particular, the Mississippi River rose to a near-record 6 m (20 ft) crest in Minneapolis-St. Paul, forcing the closing of some roads. The mayor of St. Paul, MN declared a state of emergency for this area.

Fig 1. Map of Great Lakes highlighting significant events in Summer of 2014
Long description

Figure 1: Map of the Great Lakes highlighting the significant events that occurred in the summer of 2014. Wet conditions dominated across the Great Lakes basin this quarter resulting in water levels rising more than usual for this time of year on each of the Great Lakes, except Lake Ontario. Lake Superior was not ice-free until June 6, making it the latest ice-out date in 40 years of recordkeeping. In mid-August, heavy rainfall in Detroit, MI and Windsor, ON caused significant flooding of homes and major transportation corridors. A harmful algal bloom developed in Lake Erie this summer, impacting potable water supply in communities reliant on the lake’s water.

Regional Climate Overview - for June - August 2014

Surface Water Temperature

Surface water temperatures were colder than usual for Summer 2014. Lakes Superior and Michigan-Huron generally saw departures from near average to -6.6°C (-11.9°F) from average. Lake Ontario’s water temperatures deviated from near average to -4.6°C (-8.3°F) from average, while Lake Erie had departures from near average to -1°C (-1.8°F) from average. The below-average water temperatures were due to below-normal air temperatures and late-season ice cover.

Long-term average based on 1992-2013.


Lake Temperature: Departures from Long-term Average (°C)

Figure 2: Surface Water Temperature: Departures from the long term average (°C) from June 1 to August 31, 2014. 

Water temperature scale
Long description

Figure 2: Surface Water Temperature: Departures from the long term average from June 1 to August 31, 2014.  Map of the Great Lakes showing the surface water temperature departures (difference) from the long term average in degrees Celsius.  In general all the Great Lakes experienced surface water temperatures below average.  Green to blue shades depict areas with surface water temperature departures from -4oC to  -6.5oC (-7oF to -11.7oF) from the long term average and this occurred in eastern Lake Superior, eastern Lake Michigan and a small eastern section of Lake Huron.  Orange, light grey and grey shades depict areas with surface water temperature departures from -1.5oC to -3.5oC (-2.7oF to -6.3oF) from the long term average and this occurred in the central and western portions of Lake Superior, in the western and south-central parts of Lake Michigan, central and northwestern portions of Lake Huron, in western Georgian Bay and in southern Lake Ontario.  Yellow to beige shades depict areas with surface water temperature departures from average to -1.5oC (-2.7oF) from the long term average and this occurred in all of Lake Erie, northwestern Lake Superior, southern Lake Michigan and Green Bay, southern Lake Huron and Saginaw Bay, eastern Georgian Bay and northern and western Lake Ontario. 

Great Lakes Water Levels

Levels on all of the Great Lakes remain above last year’s levels at the beginning of September, with the exception of Lake Ontario, which was 2 cm (0.8 in) lower than last year. Continued wet weather contributed to Lake Superior finishing the quarter 15 cm (5.9 in) above its long-term average and 20 cm (7.9 in) above last year’s level. Lake Michigan-Huron continued to rise, finishing the quarter just 2 cm (0.8 in) below average, but 42 cm (16.5 in) higher than last year’s level. The other lakes also received above average water supplies. At the beginning of September, Lake Erie was 11 cm (4.3 in) above average while Lake Ontario was 7 cm (2.8 in) above average.

Water level statistics based on 1918-2013.

Precipitation

The Great Lakes basin received 120% of its average summer precipitation. In June, all lake basins were wetter than average, with the overall basin seeing 135% of average. July and August were wet for all lake basins but Superior. Overall, the Great Lakes basin saw 110% of average in July and 120% in August.

Map: precip normals based on 1981-2010 (NOAA, EC).
Text: precip normals based on 1900-2010 (USACE).


                   Precipitation: Percent of Normal (%)

Figure 3: Map of Great Lakes showing precipitation distribution from June 1 to August 31, 2014

snow dpt scale
Long description

Figure 3: Precipitation: Percent of Normal (%).  Map of Great Lakes showing precipitation distribution from June 1 to August 31, 2014.  Green and dark green areas depict greater than normal percentages of precipitation and they are concentrated over the majority of the US Great Lakes States with the exception of the northwest corner of Ohio. Wetter conditions also dominate over eastern and northeastern Ontario.Less than normal percentages of precipitation are depicted by brown and beige and are concentrated over central and eastern Lake Superior and its eastern shores, over northern Lake Michigan, south central Lake Huron, and over Lake Erie and southwestern Ontario.

Temperature

Summer was cooler than normal in the Great Lakes basin, with departures from near normal to -2°C (-3.6°F) from normal. July was quite cool as departures ranged from -1°C (-1.8°F) to -3°C (-5.4°F) from normal. August was also cool, with departures from near normal to -2°C (-3.6°F) from normal. June was the only warmer-than-normal month, with departures from near normal to +2°C (+3.6°F) from normal.

July 2014 selected to display greatest anomalies
Temperature normals based on 1981-2010.


Temperature: Departure from Normal (°)

Map of the Great Lakes showing the temperature departures from normal for July 2014

Great Lakes temperature scale
Long description

Figure 4: Temperature: Departure from Normal for July, 2014. Only July 2014 was depicted to display the greatest temperature anomaly in the summer of 2014. Map of the Great Lakes showing the temperature departures from normal in degrees Celsius. Purple and dark purple areas depict areas where the temperature was -2°C to -5°C (-3.6°F to -9°F) below normal and this occurred throughout the entire Great Lakes region with the greatest temperature departures in areas surrounding and to the south of Lake Michigan. Light purple and white areas depict areas where the temperature was near normal to -1vC (-1.8°F) and this occurred to the southeast of Lakes Erie and Ontario into Pennsylvania and New York and the south of the St. Lawrence River, extending eastward into Quebec.

Regional Impacts - for June - August 2014

Water Quality

The harmful algal bloom in Lake Erie created toxic, undrinkable water for residents and businesses in the western Lake Erie area. On August 2, city of Toledo and Ohio state officials informed residents of Toledo not to use their tap water (restrictions were lifted on August 4). Many businesses reported lost revenue since they had to close during the water emergency. The governor of Ohio declared a state of emergency for Lucas, Wood, and Fulton counties and said that officials were working to have drinking water shipped for affected residents. On August 26, residents of Pelee Island, ON were advised not to drink the water (restrictions were lifted on September 9). The water emergencies put a spotlight on Lake Erie’s algae problem, which has been occurring for more than a decade. To try to combat this issue, Ohio is receiving $2 million in new federal emergency funds to reduce runoff in the western Lake Erie basin.

Navigation & Recreation

The recent rise in water levels has been beneficial to the shipping and recreational boating community on the Great Lakes. The Lake Carriers Association cited an example of a carrier leaving Duluth, MN in June 2014 that was able to transport over 2,000 more tons of cargo compared to this same time last year. Marina owners had more slips to sell and required less dredging. Boaters and fisherman were able to access areas on the lakes that they could not access before.

Public Health

The lack of hot temperatures this summer helped reduce the typical summer occurrence of smog/ozone pollution. In fact, the Ontario Government and Environment Canada did not issue any Air Quality Advisories this summer for the Canadian Great Lakes basin. In the U.S., Ozone Action Days were only issued in Michigan (Detroit and southwest) from July 20-22 by the Michigan Department of Environmental Equality. In addition, the heat wave was missing in action this summer across the basin, with many locations only experiencing less than half their normal number of 30°C+ (86°F+) days for the summer. The absence of heat waves resulted in less heat stress, which is a positive effect on the public health of the basin.

Infrastructure & Transportation

Several Great Lakes cities felt infrastructure and transportation impacts related to flooding this summer. The Detroit, MI flooding event on August 11 left thousands of motorists stranded on flooded freeways and streets, many of which remained closed for days. Delivery interruptions and absenteeism slowed automobile production in Detroit. On June 20, heavy rains produced a massive mudslide behind a University of Minnesota Medical Center, dumping 1.8 m (6 ft) to 2.4 m (8 ft) of mud and tree debris on a parkway below.

Regional Outlook - for October - December 2014

Lake Level Outlook

The fall season is the time of year when water levels are typically in a seasonal decline. Current outlook for October through December indicate that levels on lakes Superior and Erie are expected to remain 9 cm (3.5 in) to 14 cm (5.5 in) above average unless exceedingly wet or dry water supply conditions are experienced. Lake Michigan-Huron is expected to rise above average unless dry conditions return. Lake Ontario is expected to drop a few centimeters below average unless above average water supplies are received.

Forecast of October-December 2014 Water Levels (compared to the long-term average)
Lake Forecasted high
compared to the
long-term average
in centimetres
Forecasted low
compared to the
long-term average
in centimetres
Forecasted high
compared to the
long-term average
in inches
Forecasted low
compared to the
long-term average
in inches
Superior +25 cm above -3 cm below +9.8 in above -1.2 in below
Huron-Michigan +18 cm above -14 cm below +7.1 in above -5.5 in below
Erie +34 cm above -10 cm below +13.4 in above -3.9 in below
Ontario +12 cm above -19 cm below +4.7 in above -7.5 in below

Outlook from the US Army Corps of Engineers and Environment Canada (October-September 2014)

Temperature and Precipitation Outlook

Environment Canada (EC) and the Climate Prediction Center (CPC) are forecasting greater chances for above normal temperatures for October through December for their respective Canadian and U.S. Great Lakes basins. However, both EC and the CPC indicate there is no clear signal on whether precipitation will be above, near, or below normal for their basins for the same time period.

El Niño has a 60-70% chance of developing by mid to late fall. Based on previous years, El Niño winters tend to be warmer than normal in the Great Lakes basin, with drier than normal conditions in the eastern basin, less snow than usual, and reduced ice cover on the lakes.

Harmful Algal Bloom Outlook

As of early September, the harmful algal bloom still persists in western Lake Erie and has now reached the northern shore of the west central basin. However, the size and toxicity of the bloom have decreased since the bloom peaked in early August. According to researchers, harmful algal blooms in Lake Erie typically dissipate by the middle to end of October. Until the 2014 algae bloom dissipates, monitoring of contamination levels of drinking water in the Toledo area is ongoing.

Contact Information

Contact for NOAA:

Molly Woloszyn: mollyw@illinois.edu
Samantha Borisoff: Samantha.borisoff@cornell.edu

Contact for Environment Canada:

greatlakes-grandslacs@ec.gc.ca
enviroinfo@ec.gc.ca

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