Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

 

Thwaite Scars (SD 762 708) – Four reclassified to 400m Sub-Four

There has been a reclassification to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Thwaite Scars (SD 762 708)

The criteria for the list that this reclassification applies to are:

The Fours – The 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are three categories of sub hills, with this hill being reclassified to the 400m Sub-Four category, the criteria for which are all English hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Thwaite Scars and it is adjoined to the Whernside group of hills, which are situated in the central Pennines, and it is positioned with the A465 road to its south-west and a minor road to its south-east, and has the village of Austwick towards the south south-east.

When the 2^nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was included as a Four and listed with 30m of drop, based on the 408m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 378m col spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the reclassification of this hill to 400m Sub-Four status is due to LIDAR analysis, resulting in a 407.1m summit height and a 377.7m col height, with these values giving this hill 29.4m of drop, which is insufficient for it to be classified as a Four. 

 

The full details for the hill are:

Group:  Whernside

Name:  Thwaite Scars

OS 1:50,000 map:  98

Summit Height:  407.1m (LIDAR)

Summit Grid Reference:  SD 76287 70892 (LIDAR)

Col Height:  377.7m (LIDAR)

Col Grid Reference:  SD 76737 71921 (LIDAR)

Drop:  29.4m (LIDAR)

 

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

The Fours – 400m Sub-Four

 

The Fours – 390m Sub-Four

 

The Fours – 390m Double Sub-Four

 

Myrddyn Phillips and Aled Williams (April 2023)