Seasonal Summary Eastern Canada Winter 2023-2024

Summary for the East Coast

Ice first appeared in the East Coast waters in late November. Temperatures were colder than normal during November, with ice forming along the coasts of the Labrador Coast north of Lake Melville, along the shores of Lake Melville, and along parts of the coast of the Gulf of St. Lawrence. November would be the only month this ice season that would have below normal temperatures as the average air temperature for every month after November was warmer than normal.

The main driver of sea ice formation is air temperature. Warmer than normal air temperatures this season led to both a late start to the ice season as well as to lower than normal ice coverage over the East Coast. This season was one of the lowest ice coverage years for the East Coast.

In the Gulf of St. Lawrence, significantly warmer than normal water surface temperatures also hindered the formation of sea ice. Also, the ice coverage over the Gulf of St. Lawrence was the lowest on record.

Temperatures during the 2023-2024 ice season

November was colder than normal and saw ice formation begin along the Labrador and St Lawrence coasts and along the shores of Lake Melville. However, December and every other month of this ice season averaged with warmer than normal air temperatures which hindered further ice formation on the East Coast.

Air temperatures were warmer than normal in December and January over the entire East Coast waters. Temperatures averaged 4-5 °C above normal over the western Gulf of St. Lawrence and the mid-Labrador Coast in January. Very little ice formation occurred until after the first week of January when, though temperatures remained warmer than normal, they were cold enough to form ice in sheltered areas along the south Labrador Coast.

It was not until the third week in January that ice coverage started to pick up in the St. Lawrence, along the North Shore of Quebec and in the Northumberland Strait. At the end of January, the ice coverage along the south Labrador Coast had expanded away from the coast to near normal coverage values. At this time ice also moved into the Strait of Belle Isle and along the Northern Peninsula in Newfoundland and Labrador.

Late January and February saw a short period of cold temperatures arrive over Newfoundland and Labrador and the eastern Gulf of St. Lawrence, while the western Gulf of St. Lawrence remained near normal temperatures. Temperatures remained near normal over the western Gulf.

February had the greatest amount of ice coverage in the East Coast with the maximum ice coverage on the East Coast waters occurring on the 26^th of February. Though February 26^th was also the week with the maximum ice coverage for the Gulf of St. Lawrence the only areas with significant ice coverage were the St. Lawrence, the Strait of Belle Isle, and the Northumberland Strait north to Gaspe. Figure 7 shows in red how large an area in the central Gulf of St. Lawrence that normally would be ice covered had no ice cover. This large an area with no ice cover that would normally be ice covered occurring during the time when the Gulf of St. Lawrence experienced its maximum ice coverage for this season highlights how little ice was on the Gulf of St. Lawrence this year.

For the Gulf of St. Lawrence this season would end up being a record low ice coverage season.

With the arrival of March, the only area with appreciable amounts of sea ice was the Strait of Belle Isle where thicker ice that what had been present in the Gulf of St. Lawrence would continue feeding ice into the Strait as it flowed south along the Labrador Coast. The remainder of the Gulf of St. Lawrence lost almost all its ice coverage at this time.

The Gulf of St. Lawrence went from its maximum ice coverage this season on February 26^th with ice covering large areas of the estuary and the Northumberland Strait to having almost no ice cover outside of Chaleur Bay and the Strait of Belle Isle after the first week of March. By the end of the second week in March all the ice in Chaleur Bay also melted. This rapid melt was due to the warm temperatures through the year not allowing the sea ice to thicken and with the arrival of warmer spring air temperatures the ice, which was substantially thinner than normal, quickly melted.

April like March was a warm month in most regions being 0.5-1.5 °C above normal in the Gulf of St. Lawrence and Newfoundland and 1-2 °C above normal along the mid-Labrador Coast.

Though the Gulf of St. Lawrence ice season had effectively ended early in March, the ice coverage along the south Labrador Coast and northern East Newfoundland Waters were at normal amounts as by this time ice had moved south into the areas from farther north with the Labrador current.

Figure 9 above shows almost the entire Gulf of St. Lawrence as being without ice cover by March 11^th and that during this period the Gulf of St. Lawrence is usually covered with ice. Looking at the south Labrador Coast in Figure 9 we see that ice coverage is almost normal.

The air temperatures remained well above normal for March and April along the Labrador Coast so that as the ice brought south by the Labrador current increased the ice coverage to near normal levels in March it was also melting and thinning faster than it would normally and in April the ice coverage quickly started to disappear from southern areas of the south Labrador Coast and from the east Newfoundland waters.

By the end of April only Lake Melville and the areas of the mid-Labrador Coast north and east of Lake Melville had any ice coverage. Continued warmer than normal air temperatures finally melted the ice in Lake Melville by May 20^th and at this time the only ice that remained in the East Coast was along the mid-Labrador Coast north of Lake Melville. The last of the ice on the East Coast disappeared after the second week in June.

The East Coast had a slow start to the ice season due to warm temperatures during December when ice normally first starts to form. The amount of ice present in the East Coast was a third its normal amount until about mid-March when ice that had formed farther north began to move into the East Coast area and increased the amount of ice coverage to be about half its normal value for the remainder of the season.

Seasonal TAC for the East Coast for the 2023-2024 season was 3.4%. This is the 4^th lowest TAC for the East Coast since the 1971-1972 season. The ten lowest TAC years for the East Coast have all occurred since 2000-2001 season.

The maximum ice coverage for the East Coast was the week of February 26^th. See Figure 6 above which shows the ice coverage for the East Coast on this date. This season’s maximum ice coverage for the East Coast was the fourth lowest recorded since 1973. The five lowest maximum ice seasons for the East Coast have all occurred since 2010.

Gulf of St. Lawrence

The first ice appeared in the Gulf of St. Lawrence at the end of November and early December in sheltered bays along the coast of the St. Lawrence and along the coast of the North Shore of Quebec. Figure 15 below shows the mean air temperature over the Gulf of St. Lawrence during December and the teal blue color in northern areas that saw ice formation averaged between -5 to -7 °C.

The ice coverage on the Gulf of St. Lawrence remained unchanged until the first week in January when ice started to appear along the coast of Prince Edward Island, along the coast in Northumberland Strait and in Chaleur Bay. The ice coverage also increased in the western half of the St. Lawrence where the ice coverage completely covered the river at this time.

The mean air temperature during January over the Gulf of St. Lawrence was between -7°C in the south and -14°C along the North Shore of Quebec. The only further increase in ice coverage occurred at the very end of January as ice began to move into the Strait of Belle Isle for the south Labrador Coast.

This year’s TAC of 1.2% over the Gulf of St. Lawrence, calculated to the end of January, was the second lowest ever recorded from the start of a season to the end of January. The lowest recorded was last season and the third lowest on record was the 2020-2021 season.

The five lowest TAC values on record for the Gulf of St. Lawrence, calculated to the end of January for each season have all occurred since the 2015-2016 season. This could indicate that the start of the ice season is becoming delayed over the Gulf of St. Lawrence. This delay in the start of the ice season is probably due to a combination of both warmer air temperatures and warmer sea surface temperatures.

The later start to the ice season would also mean that the ice has less time to thicken during the winter and thus could melt sooner leading to a shortened ice season over the Gulf of St. Lawrence.

February saw an expansion of the ice coverage with the St. Lawrence as well as the Estuary as well as the Northumberland Strait being covered in ice by the end of the first week in February. Ice would move into the Strait of Belle Isle during the first week of February covering the Strait in ice at this time. As the month continues the only area that would see ice development was Chaleur Bay that became covered in ice by the end of February. The remainer of the Gulf of St. Lawrence would remain essentially without ice coverage.

The maximum ice coverage for the Gulf of St. Lawrence would occur on February 26^th.  Figure 6 above shows the ice coverage analysis for February 26^th. Figure 7 above shows the departure from normal on February 26^th which shows in red the areas that would normally have ice coverage on this date that were ice free this year. The area in red showing the `missing’ ice compared to normal ice coverage covers all the central Gulf of St. Lawrence including Anticosti Island and the Îles-de-la-Madeleine.

Very quickly after the Gulf of St. Lawrence attained its maximum ice coverage on February 26^th almost all the ice coverage that was not in the Strait of Belle Isle was gone by the end of the first week in March. The reason for the rapid disappearance of the ice cover was that much of the ice had been recently formed during a brief period of colder air temperatures but was still thin and with the arrival of spring and warmer temperatures quickly disappeared.

Figure 20 below shows the departure from normal chart for March 4^th showing how little ice remained after this rapid melt at the start of March — a mere week after the Gulf of St. Lawrence had reached its maximum ice coverage.

By the end of the second week in March only a few sheltered areas along the North Shore of Quebec and the Northumberland Strait had ice in the Gulf of St. Lawrence. There was still ice present in the Strait of Belle Isle as it would keep arriving as it moved south along the Labrador Coast.

This year’s TAC of 3.1% over the Gulf of St. Lawrence, which was calculated to the end of March, was the lowest ever recorded value for the TAC to the end of March.

The five lowest TAC values on record for the Gulf of St. Lawrence, calculated to the end of March for each season, have all occurred since the 2009-2010 season.

Figure 17 above shows the later start to the ice season this winter and in recent years. It is discussed below Figure 17 that this later start of the ice season could also mean that the ice had less time to thicken during the winter and thus melted sooner, which led to a shortened ice season over the Gulf of St. Lawrence.

Figure 21 above shows that this year ice coverage at the end of March near the end of the season was in fact the lowest on record. Figure 21 above also shows that the five of the lowest TAC amounts calculated at the end of March for each season all happened in the last fifteen years. This could indicate a trend to a shortened sea ice season over the Gulf of St. Lawrence.

With the arrival of April and warmer air temperatures the ice along the south Labrador Coast would melt before reaching south far enough to enter the Strait of Belle Isle and by the third week in April the Strait of Belle Isle was also free of ice bringing the 20232024 Gulf of St. Lawrence ice season to an end.

Warmer than normal sea surface temperatures every month this season combined with the warmer than normal air temperatures for every month after November and resulted in the sea ice forming later in the year than it normally does, and not forming as much ice coverage as is normal. As the ice doesn’t thicken as much as it usually does the spring melt occurred much sooner than normal. In brief, a shorter ice season with much less ice because of both warmer than normal air and water temperatures persisted this season.

This year’s ice season was significantly shorter than normal by almost two months as shown in Figure 25 above or Figure 26 below by the vertical blue bars reaching near zero after the middle of March.

The greatest amount of ice cover on the Gulf of St. Lawrence occurred during the last two weeks of February with 11% ice cover. Normally, during the last two weeks of February as shown in the figure above the amount of ice cover is 36%.

January is usually the month that the ice coverage in the Gulf of St. Lawrence starts to increase from an average of 3% at the beginning of the month to reach over 20% by the end of the month. Ice cover then normally remains over 35% for February.

This season, as Figure 26 above shows, ice coverage in the Gulf of St. Lawrence remained below 2% for most of January before briefly reaching 4.9% on the 22^nd of January before dropping back to 2.6 per cent by the end of the month. The average ice coverage for the end of January is over 21%.

January 2024 had the second-lowest ice coverage for any January ice cover for the Gulf of St. Lawrence since records began in 1969, see Figure 17 above. This year also tied for the lowest maximum ice coverage over the Gulf of St. Lawrence to the end of January for any season since records began at 11.6% with the 2010 season.

By mid-March the ice cover quickly dropped to almost zero over the Gulf of St. Lawrence with the only ice remaining ice coverage beyond the Strait of Belle Isle being in protected bays and inlets along parts of the coasts. This rapid decline in the ice cover seen in the figure above. The rapid drop to near zero of the blue histograms representing the percentage of ice cover was due to the warm temperatures quickly melting the thin ice. The ice was thin as the entire winter experienced warmer than average air temperatures every month this season, which did not allow the ice to thicken. Warm temperatures and the very warm sea surface temperatures also meant that the ice season had a very late start to the ice season with sea ice forming almost a month later than normal.

The TAC for the 2023-2024 Gulf of St. Lawrence ice season was 1.9%. This year’s TAC for the Gulf of St. Lawrence is 1.9% and is the lowest TAC on record. The twelve lowest TAC years on record for the Gulf of St. Lawrence have all occurred since the 2005-2006 season.

The maximum ice coverage for the Gulf of St. Lawrence this season was 11.6% and occurred the week of February 26^th. This season’s maximum ice coverage for the Gulf of St. Lawrence was tied for lowest maximum ice coverage on record with the 2010 season. The seven lowest maximum ice seasons for the Gulf of St. Lawrence have all occurred since 2010.

South Labrador Coast

With air temperatures warmer than normal every month of the 20232024 season the ice was slow to form along the south Labrador Coast. Usually, sea ice coverage starts to grow during the month of December. However, this year with December air temperatures being 4-5° C warmer than normal, only small amounts of ice formed in sheltered areas along the coast. The warm air temperatures continued in January, which was once again 4-5° C warmer than normal, and this kept the ice coverage at about 10% its normal value for January.

By the end of January temperatures were cold enough to allow the ice coverage to increase to near 60% of its normal value for the end of January and remain at those levels until the end of the season.

The last of the ice in south Labrador Coast melted in mid-June off the shore of mid-Labrador Coast, northeast of Lake Melville. By this time, the southern Labrador Coast was ice free for a month as the last ice off the coast south of Lake Melville had melted 3 weeks earlier than normal in mid-May. The ice melted earlier than normal here because of warmer than normal temperatures for every month this winter meant that the ice was thinner than it would normally be and therefore would melt quicker than it normally would.

The single season ice chart for the south Labrador Coast, Figure 29 below, does not show as dramatic a decrease in the ice coverage compared to the charts for the Gulf of St. Lawrence or the east Newfoundland waters. This is because as the ice drifted southwards towards the south Labrador Coast from more northern regions, it had more time to thicken. This ice therefore was somewhat thicker and therefore took longer to melt. On average, the ice over southern parts of the south Labrador Coast was 40-60 cm thinner than normal. Farther north, the ice was on average only 20-40 cm thinner than normal. Because of this, the ice season ended a month early, after the second week in May, south of Lake Melville. It ended about 2 weeks early near Lake Melville and about a week early in the most northern sections of the south Labrador Coast.

The 2023-2024 ice season over the south Labrador Coast was slightly below normal for almost the entire season. From February to the end of the season, the ice coverage averaged about 60-70% of the normal amount. For the first two weeks of March, it is seen that the ice coverage amounts were equal to or slightly above the historical normal.

Also apparent on Figure 29 is the slow start to the 2023-24 ice season.

Warmer than normal air temperatures were experienced all winter, and this slowed the formation of ice along the south Labrador Coast. It was not until the ice that had formed much farther north flowed south with the Labrador current at the end of February and reached the south Labrador Coast that ice coverage amounts over the south Labrador Coast, which were 20% of their normal amounts during December and January, reached near normal ice coverage amounts.

The TAC for this ice season for the South Labrador Sea was 7.8%. This represents about a third less ice than the long-term median of 11.8% for the South Labrador Sea. This year’s ice season was the 6^th lowest TAC on record for the South Labrador Coast.

The maximum ice coverage for the south Labrador Coast this season was 23% and occurred the week of March 12^th. This season’s maximum ice coverage for the south Labrador Coast was slightly below the long-term median value of 26%.

East Newfoundland Waters

Figure 32 below shows that the ice season for the east Newfoundland waters started about a month later than is normal and that even at its peak ice coverage during late February and March it had only about 35% as much ice coverage as would normally be expected. In addition, Figure 32 below shows that the ice season ended very abruptly at the end of March as the ice was thin and was quick to melt with the arrival of warm temperatures.

At the end of March and the start of April there was less than 1% ice coverage over the east Newfoundland waters when normally during this period ten times this amount of ice is observed. The ice coverage at this time is important both for protecting icebergs from erosion by the sea as they move southwards into Newfoundland waters and for the seal population that uses the ice floes.

The ice season this year in the east Newfoundland waters effectively ended after the first week in April with only tiny amounts of ice remaining after this time. This would represent a two-month earlier than normal end to the ice season. Officially, the last piece of ice in the east Newfoundland waters disappeared by the end of April, a month earlier than is normal. The ice this season was on average 40-50 cm thinner than normal because from December to the end of the ice season, every month had warmer than normal average air temperatures. The sea ice did not form until later in the season. Forming later and continuing to experience warmer than normal air temperatures ensured that the ice did not thicken as much as it would normally. In addition to the ice that formed in the east Newfoundland waters being thinner than is normal the ice that formed farther north also experienced warmer than normal average air temperatures every month this season so that it also did not thicken as much as it would normally as it slowly drifted southwards along the Labrador Coast on its journey to reach the east Newfoundland waters.

The TAC for this ice season for the east Newfoundland waters was 0.7%. This TAC is less than a third the long-term median TAC of 3.2% for the east Newfoundland waters. This year’s ice season was the 4^th lowest TAC on record for the east Newfoundland waters.

The maximum ice coverage for the east Newfoundland waters this season was 4.7% and occurred the week of March 12^th. This season’s maximum ice coverage for the east Newfoundland waters was the 5^th lowest maximum ice coverage on record. The seven lowest maximum ice coverage seasons have all occurred since the 2004 season for the east Newfoundland waters.

Notes:

Total Area Coverage (TAC): The “Total Accumulated Ice Coverage” (TAC) represents the average quantity of ice coverage over a geographical area for a specified period. It is expressed as a fraction or percentage of the region with values ranging from 0 (no ice) to 100% (area (not volume) fully covered with ice over the entire period). It is a good indication of average ice conditions during the winter and useful for year-to-year comparison.

NCEP/NCAR Reanalysis charts and Sea surface temperature anomalies from The NOAA Physical Sciences Laboratory (PSL) 

All other charts and data are found on the Ice applications and data page.