Daily Commentary
Can I see an iceberg?
Why can't I see an iceberg?
Current iceberg map
This map shows the locations of icebergs off-shore from Dunedin, New Zealand. Triangles indicate the most recently measured position of the closest iceberg(s). Previous iceberg locations are shown by crosses with the dotted lines indicate the path of iceberg movement. Icebergs shown in blue are no longer being monitored; the date shown is when the iceberg position was last measured. The iceberg locations are provided by Helicopters Otago and will be updated by 6pm daily.
Note: there are currently no icebergs known to be close to Dunedin, and there are no further updates of this webpage planned.
Iceberg positions at 4pm Saturday December 2 2006
Tuesday 5 December 2006: The icebergs that were expected to move closer to Dunedin over the weekend are still not close enough for helicopter flights. It is not expected that flights will resume until Thursday at the earliest, so we are unable to provide updated locations at this time.
Saturday 2 December 2006: The group of three icebergs has continued to move north (and slightly west) over the last 24 hours. They have slowed slightly to 0.7 km per hour and covered 17 km. At 4 pm the icebergs were approximately 100 km from Mt Cargill on a line through Taiaroa Head. These icebergs will no longer be tracked by us, but may remain visible for the next day or so. There are reports of another group of icebergs heading north towards the Dunedin coast, but they are not expected to be close enough to view until Tuesday.
Friday 1 December 2006: In the 24 hours from 4 pm Thursday to 4 pm Friday, the group of three icebergs had moved 20 km north-east, at an average speed of 0.8 km per hour. At 4 pm, they lay 102 km slightly north of east from Mt Cargill, on a line of sight slightly to the right of Otakou & Harington Point.
Thursday 30 November 2006: There were no helicopter flights this morning due to the bad weather. When flights resumed at lunch-time the closest icebergs (a group of three) had moved 22 km north-north-east at an average speed of 1.1 km per hour. During the day the icebergs started moving in a more northerly direction and speeded up to 2.5 km per hour. At 4 pm the icebergs were 91 km slightly south of east from Mt Cargill. At their current rate of movement these icebergs will only be visible for the next 1 - 2 days
Wednesday 29 November 2006: A new iceberg was located by helicopters 13 km further off-shore from the group of three closest icebergs currently being visited. This group has been moving steadily north-east over the last 24 hours at around 1.3 km per hour and now lies approximately 92 km from Mt Cargill on a compass bearing of 115 degrees (look between Broad Bay and Portobello). The new iceberg was 106 km from Mt Cargill at 7 am this morning, and slightly south of the group of three. All of these icebergs are just within viewing range in good weather conditions.
Tuesday 28 November 2006: The group of three icebergs has continued moving north-east. It moved 15 km at an average speed to 1.8 km per hour overnight and 1.8km at an average speed of 2 km per hour today. These icebergs were 97 km south-east of Mt Cargill at 4 pm and will be visible in good weather conditions.
Monday 27 November 2006: The iceberg that has been tracked over recent days is now well north-east of Dunedin and is no longer being visited by helicopter flights. Aerial reconnaissance on Sunday evening located another group of icebergs approaching from the south. The location of the closest icebergs, a cluster of three, is shown on the map. At 4 pm, they were 102 km south-southeast of Mt Cargill on a compass direction of 153 degrees east of true north. From Mt Cargill, this puts them on a line of sight through the middle of Macandrew Bay, and slightly to the left of Highcliff Hill. In very clear weather they will be visible from Mt Cargill and Flagstaff, sitting right on the horizon. Between 7 am and 4 pm today, they moved 18 km northeast, an average speed of 2 km per hour. If they continue their present track, they should lie about 90 km southeast of Mt Cargill about midday Wednesday, and should be clearly visible with binoculars if the weather is very clear.
Sunday 26 November: The largest and closest iceberg moved 26 km north-northeast overnight Saturday (an average speed of 1.5 km per hour). Between 8.45 am and 4 pm Sunday it moved a further 8.5 km (an average speed of 1.2 km per hour). At 4 pm, the iceberg was 129 km away from Mt Cargill on a compass direction of 85 degrees east of true north. From Mt Cargill, this puts it on a line of sight just to the right of Otakou and Harington Point. Assuming that the iceberg is about 100 m high, only the very top of the iceberg would be visible from Mt Cargill, even in perfectly clear weather conditions. By Monday this iceberg will be completely beyond sight of land, and aircraft will be the only way to see it. Helicopter pilots report that it still looks spectacular from the air. At 4 pm the iceberg was 114 km south-southeast of Moeraki and 148 km southeast of Oamaru, but is well out of sight over the horizon from these locations.
Saturday 25 November: The largest and closest iceberg moved 33 km north-northeast overnight (an average speed of 2.2. km per hour), but during Saturday has only moved 4.5 km (an average speed of 0.5 km per hour). Helicopter pilots estimate that the iceberg is 350 metres long by 200 metres wide and its highest point is about 100 metres above the sea. At 10.30 am, a helicopter flight that was circling the iceberg observed the sudden collapse of a large mass of ice from the northeast side of the iceberg. This caused the whole iceberg to tilt up considerable to the south in a time of less than 2 minutes. This highlights that icebergs are dangerously unstable. At 4 pm, the iceberg was 116 km away from Mt Cargill on a compass direction of 100 degrees east of true north. From Mt Cargill, this puts it on a line of sight just to the left of Hoopers Inlet and Mt Charles. No other icebergs were visited today by Helicopters Otago. So far today, conditions out to sea have been too hazy for the iceberg to be seen from Mt Cargill. If the iceberg continues at its present rates and directions of movement, it will be getting further away from land. Sunday and possibly Monday are likely to be the last times that this iceberg may be visible from Mt Cargill (but only if weather conditions out to sea are good and clear).
Friday 24 November: The largest and closest iceberg has been moving erratically since Thursday. Overnight, it moved northeast 25 km, but today it has moved northwest by only 2 km. Apparently the directions and speeds of the currents are varying a lot. Its average speed overnight was 1.7 km per hour. Today its average speed has been just 0.2 km per hour. It was visible from Mt Cargill at 6.30 am this morning before a southwest change reduced the visibility. At 4 pm, the iceberg was 113 km away from Mt Cargill on a compass direction of 119 degrees east of true north. This puts it on a line of sight just left of Mt Charles. The icebergs further offshore were not visited today.
Thursday 23 November: The largest and closest iceberg had changed course overnight and moved in a more easterly direction, before returning to a more northeasterly track through the day. Its average speed in the last 24 hours has dropped to almost 0.5 km per hour. At lunchtime on Thursday, air conditions were very clear out to sea and the iceberg was clearly visible by binoculars from the top of Mt Cargill, although was lost from view at 3 pm when visibility decreased following a southwest wind change. At 4 pm, the iceberg was 115 km offshore from St Clair Beach at a compass direction of 127 degrees east of true north. On Thursday morning, helicopter flights detected 3 new icebergs, between about 155 km and 180 km southeast of St Clair.
Wednesday 22 November: Today only the largest and closest iceberg has been visited by helicopter flights; there is no information on today's locations of the second largest iceberg, 10 km further off-shore. Today, the largest iceberg has been moving at an average speed of 1.3 km per hour, and at 4 pm on 22 November, it lay 114 km off St Clair Beach, Dunedin, at a bearing of 132 degrees.
Tuesday 21 November: Today the largest and closest iceberg has been moving northeast at an average speed of 0.9 km per hour, while the second largest iceberg further offshore is moving less quickly at 0.75 km per hour. At 4 pm on 21 November, the largest iceberg lay 123 km off St Clair Beach, Dunedin, at a bearing of 146 degrees. At this distance it cannot be seen from land, because of the curvature of the earth. If it continues on its present path, it is expected to lie within 100 km of Dunedin in about 2 days time, and in clear weather should be visible (using binoculars) from the highest peaks in Dunedin, such as Flagstaff or Mt Cargill.
Can I see an iceberg? Am I in the right place?
An iceberg came within sight of the highest hills, easily accessible, in Dunedin between 22 and 25 November 2006. The iceberg was (in very clear weather) visible on the horizon from the summits of Mt Cargill and Flagstaff. From these vantage points, both approximately 660 m above sea level, there is a 100 km line of sight to the horizon out to sea.
Objects more than 100 km away lie over the horizon and will be visible only if they are riding high in the water. For example, the top of a 60 m high iceberg will be visible if it is less than 30 km over the horizon (i.e. within 130 km of an observer on Mt Cargill or Flagstaff). The height of the 22 ? 25 November iceberg was not known exactly, but helicopter pilots guessed that it was generally up to about 60 m above the water. As long as it lay within 120 km or so of Mt Cargill or Flagstaff, it was theoretically visible in very clear weather conditions.
Moderate-power binoculars were needed in order to see any detail of the iceberg. Generally once you know where to look, an iceberg that is above the horizon can just be seen with the naked eye, where there are clear weather conditions out to sea.
An iceberg lying more than about 120 km away will have so little of its surface sticking up above the horizon that it will be very hard to spot, and beyond 130 km, it will be out of sight to land-based observers, even in the clearest weather conditions. In this case, helicopters or planes would be the only way to get a look at an iceberg.
All other easily accessible hills in Dunedin and throughout coastal Otago are nowhere near high enough to have got a view of the 22 - 25 November iceberg.
Why can't I see an iceberg? Are the weather conditions right?
If an iceberg is known to be within sighting distance of the highest vantage points in Dunedin, you will only see it if you have at least 100 km clear visibility out to sea. Most of the time, conditions are not this clear. Haze, fog or spray out to sea means that the visibility is generally much less than 100 km, and view of any icebergs will be hopelessly obscured.
Visibility conditions can improve or deteriorate very rapidly (in matters of minutes). The following tips will help you decide if it is likely to be worthwhile making the trip to a high-enough vantage points to see an iceberg.
Tip 1: how sharp is the line where the sea meets the sky?
From any of Dunedin?s hill suburbs, look out to sea. If the horizon where sea meets sky is a sharp clear line, then visibility is good, and may possibly be good enough to see an iceberg if you go to Mt Cargill or Flagstaff. If the horizon looks fuzzy from the hill suburbs, there is no chance that visibility will be good enough to see an iceberg from Mt Cargill or Flagstaff.
Tip 2: how humid is the air?
If the air is humid, thin haze or mist will be widespread, especially out to sea, and there will be very little chance of visibility being good enough to see an iceberg from Mt Cargill or Flagstaff. Check the local online automatic weather stations to check on humidity. The Otago University Energy Studies weather station on campus is updated every 5 minutes. If the humidity (the blue line) is more than 50%, there is very little chance that conditions will be clear enough to see an iceberg from Mt Cargill or Flagstaff. The most favourable conditions for clear views out to see are if the humidity is less than 30% and there is a moderate to strong west or northwest wind. You can also go to the Metservice website to get an up-to-date prediction of when rain, and its accompanying humidity, is forecast to pass over the Dunedin area. The periods in-between the rain bands are likely to offer clearer conditions out to sea. However, Tip 1: seeing a clear boundary between sea and sky is a much more certain indicator of good viewing condition out to sea, than on-land humidity or weather forecast maps.
Tip 3: The iceberg shows up best when the sun is shining on it.
If it is very cloudy an iceberg will be a much duller white and harder to see. In the twilight before sunrise or after sunset, an iceberg will be very hard to see.