Nowadays Positive lightning study has a great interest in the international community committees related with this subject, specially those about Power Quality due to its effects on different equipments because of its mayor amount charge and some other characteristics that make it more destructive. This paper presents the preliminary results of a study about changes of lightning parameters values in Colombia such as polarity and stroke density when strokes of less than 15 kA detected by Colombian Lightning Location Systems (LLS) are removed. This study was carried out with the Colombian LLS data of 5 years (1997-2001) in order to determine if some, very high, Colombian Ground Stroke Density (GSD) vales, detected in preliminary studies, where overestimated, due to the inclusion of positives strokes with low current amplitude values.