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

 

Blackkip (NT 799 043) – 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 derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Blackkip (NT 799 043)

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 is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillipsand Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

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

The name the hill is listed by is Blackkip, and it is adjoined to the Thirl Moor group of hills, which are situated in Northumberland, and it is positioned with minor roads to its north, west and east, and the A68 road to its south, and has the small community of Rochester towards the south-east.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was listed with an estimated c 14m of drop, based on the 445m summit spot height positioned at NT 79821 04293 that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 431m col height, based on interpolation of 10m contouring between 430m – 440m. 

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 Sub-Four status is due to LIDAR analysis, resulting in a 448.6m summit height and a 429.3m col height, with these values giving this hill 19.3m of drop, which is sufficient for it to be classified as a Sub-Four.

 

The full details for the hill are:

Group:  Thirl Moor

Name:  Blackkip

OS 1:50,000 map:  80

Summit Height:  448.6m (LIDAR)

Summit Grid Reference:  NT 79958 04358 (LIDAR)

Col Height:  429.3m (LIDAR)

Col Grid Reference:  NT 80006 04487 (LIDAR)

Drop:  19.3m (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

 

Sub-Fours

 

Myrddyn Phillips and Aled Williams (October 2024)