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

 

Great Castle How (NY 307 078) – 400m Sub-Four addition

There has been an addition 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 prompted by Joe Nuttall who produced a summit analysis programme using LIDAR, and then confirmed by LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Great Castle How (NY 307 078)

The criteria for the list that this addition 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 included in 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 Great Castle How and it is adjoined to the High Raise group of hills, which are situated in The Lake District (Region 34, Section 34B: The Central and Western Fells), and it is positioned with the B5343 road to its south and the A591 road to its east, and has the village of Grasmere towards the 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 not included in the accompanying sub list, as it was considered not to meet the criteria used for this sub category.  With its drop to an adjacent and connecting 500m spot heighted hill considered insufficient for qualification. 

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 addition of this hill to 400m Sub-Four status is due to LIDAR analysis, resulting in a 498.2m summit height and a 472.1m col height, with these values giving this hill 26.0m of drop, which is sufficient for it to be classified as a 400m Sub-Four.  With the caveat that LIDAR gives the summit of this hill higher than the adjacent and connected hill that has a 500m spot height on the contemporary Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  High Raise

Name:  Great Castle How

OS 1:50,000 map:  90

Summit Height:  498.2m (LIDAR)

Summit Grid Reference:  NY 30791 07836 (LIDAR)

Col Height:  472.1m (LIDAR)

Col Grid Reference:  NY 30551 07712 (LIDAR)

Drop:  26.0m (LIDAR)

 

Our thanks to Ronnie Bowron for bringing the details of this hill to our attention.

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 (November 2022)