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Knepper, D. H.

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TECHNICAL REPORT STANDARD TITLE PAGE
1. Report No.	 2. Government Accession No. 	 3. Recipient's Catolog No.
t	 4. TiT-ar.	 u title	 Report Dote
`	 Application of LANDSAT Data to Delimitation 	 June, 1976
of Avalanche Hazards in Montane ColoradoI	 6. Performing Organization Code
7. Authors)
	 ---
D.H. Knepper
9. erforrping Organization Home and Address
n^stitute of Arctic and Alpine Research
University of Colorado
Boulder, Colorado 80309
Sponsoring Agency Nome and Address
NASA
Goddard Space Flight Center
Greenbelt, Maryland 20771
I5. Supplementary Notes
8. Performing Organization Report No.
10.Work Unit No.
11.Controct or Grant No
13. Type of Report and Period Covered
Type II Progress
Report: 3/76-5/76
sorrng Agen.y
16. Abstract
Snow avalanche information derived directly from Landsat imagery and
indirectly from small-scale topographic maps is being used to map the
location and distribution of avalanche hazards in the Colorado Rocky
Mountains. A preliminary investigation of the usefulness of Landsat
imagery for mapping landslide areas suggests that Landsat imagery alai
is not sufficient for distinguishing between landslide and non-land-
slide areas with a high degree of accuracy.
(E76-10446)	 APPLICATIO N O? LANDSAT DATA TO
DELIMITkT I O N OF AVALANCHE HAZARDS IN FONTANE
^OLORAD j Interim ??pert, 9dr. -'g ay !976
(Colorado Univ.)	 11 p HC $3.5u	 CSCL C8L C, 3/43
N76-29076
Unclas
C 446
NIP
17. Key Words (S, l ected by Aurhor(s))
	
I8. Distribution Sfot^menl
avalanche, landslide, LANDSAT,
Colorado
19. Security Clossif. (of tfris "P.") 20. 5-curity Classif. of this page)	 21. No. of Pages	 ?2. Price*
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'For sale by the Clearinghouse for Fedcr.rl Srirntific mid Technical Information, Springlacld. Vicgini.t 22151.
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AUGi97602
SIS 1902.6
APPLICATION OF LANDSAT DATA TO DELIMITATION OF
AVALANCHE HAZARDS IN MONTANE COLORADO
Daniel H. Knepper
Institute of Arctic and Alpine Research
University of Colorado
Boulder, Colorado 80309
Contributors: D.H. Knepper
R. Summer
D. Sauchyn
N. Trench
June 1976
Interim Report for Period March 1976 - May 1976
Fourth Quarterly Progress Report
Prepared for:
Goddard Space Flight Center
Greenbelt, Maryland 20771
CONTENTS
Page
INTRODUCTION	 1
REGIONAL AVALANCHE MAPPING 	 Z
IDENTIFICATION OF MAJOR LANDSLIDE AREAS
	
5
PUBLICATIONS	 6
RECOMMENDATIONS	 6
FUNDS EXPENDED	 6
PREFACE
Over the last several years, the Institute of Arctic and Alpine
Research (INSTAAR) at the University of Colorado has been involved in
the delineation, mapping, and analysis of natural hazards in selected
portions of the Colorado Rocky Mountains. Much of this research has
been concerned with the detailed delineation of snow avalanche hazards
using air photo and field mapping techniques. Continuous monitoring of
various environmental parameters during the winter avalanche cycle has
produced significant advances in the field of avalanche prediction and
forecasting for local areas.
In June 1975, INSTAAR began research for the National Aeronautics
and Space Administration (NASA contract NAS5-20914) on a new approac ►l to
avalanche hazard investigation. The purpose of this research is to analyze,
evaluate, and apply LANDSAT imagery for delineating and mapping avalanche
hazards in the Colorado mountains. Research is currently being directed
toward six primary objectives:
(1) Compilation and analysis of historical avalanche records for
cause/effect and frequency information.
(2) Identification of avalanche hazard terrain characteristics
detectable on LANDSAT imagery.
(3) Determination of relative usefulness of LANDSAT imagery for
avalanche hazard mapping.
(4) Determination of useful schemes for cartographically representing
avalanche hazards.
(5) Using the synoptic and repetative aspects of I.ANDSAT imagery for
regional avalanche hazard mapping and analysis.
IV
(6) Examining the cost/benefits of avalanche hazard investigations.
Secondary, and purely experimental, objectives of the research project
are as follows:
(1) Investigation of potential usefulness of LANDSAT derived information
as input to avalanche forecast or warning systems.
(2) Investigation of the usefulness of LANDSILT imagery for mapping
major landslide areas.
During the report period (1 March - 31 May 1976), research was
conducted by two full-time staff members and two part-time graduate student
research assistants. Emphasis was placed on (1) applying the adopted
mapping technique to avalanche hazard mapping In the Montrose and Leadville
quadrangles (1:250,000) and (2) a preliminary investigation of the
usefulness of LANDSAT imagery as a tool for the delineation of major
landslide areas in the Colorado Rocky Mountains.
Regional mapping of avalanche hazards has, to a large extent, become
a routine process, and as the interpreters gain experience, the mapping
proceeds rapidly and proficiently. Landslide mapping, however, is still
very tentative. Although many landslide areas can be identified and mapped
on LANDSAT imagery, others show no imagery expression that allows positive
identification to be made. Reliance on the use of LANDSAT imagery as the
sole source for mapping information, therefore, is not recommended.
v
INTRODUCTION
This report summarizes the work conducted by the Institute of
Arctic and Alpine Research (INSTAAR), University of Colorado, during
the period 1 March - 31 May 1976, under contract NAS5-20914 to the
National Aeronautics and Space Administration/Goddard Space Flight
Center.
During the report period, snow avalanche hazard mapping was
conducted in the Montrose and Leadville quadrangles (1:250,000)
using Landsat imagery and the small-scale topographic information
contained on the quadrangle sheets. The mapping technique, described
in the previous progress report, works very well, and as experience
is gained, it becomes relatively fast. One man-month was also spent
investigating the usefulness of Landsat imagery for delineating the
regional distribution of landslide areas in the Colorado Rocky
Mountains. Preliminary results indicate that Landsat imagery alone
is not sufficient for locating all major landslide areas.
M
-1-
REGIONAL AVALANCHE MAPPING
Landsat imagery, in conjunction with selected supplementary information,
is being used to prepare a snow avalanche hazard map of the Colorado Rocky
Mountains. The initial ma pping is being conducted and compiled at a scale
of 1:250,000. This information will be compiled on a 1:500,000 topographic
map of Colorado when the interpretation phase of the work is completed.
To reach this point, INSTAAR has expended much time and effort in
evaluating Landsat imagery for avalanche mapping in order to better
understand its capabilities and limitations and to define any types of
additional information necessary for the accurate interpretation of the
imagery in situations where the Landsat imagery alone is inadequate. The
result is a technique that involves the visual interpretation of Landsat
imagery and the human analysis of the elevation and relief factors that
appear to be most critical in determining the avalanche hazard asVociated
with an area. The technique is practical, relatively accurate, an!i does
not rely on sophisticated (and expensive) imagery or data processing. However,
portions of the technique could be easily adapted to automatic computer
methods if the digital relief and elevation data are available in sufficient
detail.
The Technique
The technique being used to map avalanche hazards in the Colorado
mountai!:s was described in the previous progress report. Three levels of
avalanche hazard are mapped, each succeeding level being more specific on
the location of hazards and more definite on the existance of active
avalanche terrain. The lowest level consists of the definition of Poten'ial
Avalanche Terrain based on the presence of elevation (climatic) and relief
-2-
factors that could be conducive to avalanching. The intermediate level
is Interpreted Avalanche Terrain. This is terrain that is interpreted to
be active during the winter and spring avalanche cycle because of its
appearence on Landsat imagery. The highest level of avalanche hazard is
Identified Avalanche Terrain, which consists of areas that are known to
avalanche as determined by air photo interpretation, historical records,
published maps, or personal observations. A completed map expresses avalanche
hazard as actual or potential and provides the reader with the information
necessary to evaluate the reliability of what is shown on the map. A detailed,
step-by-step description of the procedures that were found to be most
efficient will be included in the final report.
Preliminary Evaluation
To date, evaluation of the mapping technique has been done by visually
inspecting the hazard maps in areas where the mappers have a degree of
familiarity. These checks have indicated that the mapping technique does
a good job of depicting the avalanche hazards, even at the small scale.
However, work is underway that will allow a more quantitative evaluation
of mapping accuracy and completeness to be made. A field team, working
under NASA Grant NGL 06-003-200, is currently preparing detailed snow
avalanche and geologic hazards maps (1:24,000) of the northern part of
Hinsdale County, Colorado. These maps will be made available at the end of
the summer field seasor. so that direct comparisons with the Landsat-
derived hazard map can be made for this previously-unmapped area.
Since the interpretation of avalanche hazards on Landsat imagery is
Influenced by the experience of the interpreter, a test will be conducted to
-3-
evaluate the variability in avalanche hazard on Landsat imagery is influenced
by the experience of the interpreter, a test will be conducted to evaluate
the variability in avalanche hazard mapping conducted by different workers.
Two areas will be independently mapped by two investigators. The resulting
maps will be compared to determine the amount and type of variation in
avalanche hazard mapping caused by different interpreters.
Between 2 and 4 weeks will be spent during the next report period
checking selected areas in the field. The areas to be checked have been
interpreted as avalanche areas, but there is no documented avalanche activity.
These areas are primarily in the backcountry and, thus, present little
actual hazard, but they provide areas in which to check the accuracy and
correctness of the interpretation procedure.
Status
The Landsat-derived avalanche hazards maps are being compiled on the
1:250,000, 2--degree topographic quadrangle maps that cover the state. Two
of these quadrangles are complete (burange and Montrose) and two are near
completion (Leadville and Craig). The remaining mountainous area in the
state is contained on four quadrangle maps, however, only one-half of this
area is within the mountains, so an equivalent of two more quadrangles remains
to be done. When these are completed, the avalanche hazard mapping will be
transferred to a 1:500,000 topographic map of Colorado.
-4-
IDENTIFICATION OF MAJOR LANDSLIDE AREAS
A secondary objective of this project was to examine the possible
usefulness of Landsat imagery as a tool for mapping major landslide areas
in the Colorado Rocky Mountains. During this report period, two graduate
student research assistants, David J. Sauchyn and Nicholas R. Trench, each
spent one month investigating the problem. They have submitted a preliminary
report on their work, but since they desire to spend two more weeks on the
study, the results of their work will not be reported until the final report.
A summary of the preliminary results is given below.
Som►c landslide areas in Colorado can be identified and delimited on
Landsat oaagery, but because of the extreme variations in the topographic,
lithologi.c, structural, and vegetational conditions associated with
landslide areas, there is no uL ►ique spectral or spatial pattern that is
indicative of landslides:
The accuracy with which landslides can be mapped is a function of the
degree to which the landslides are expressed in the relief and the topography.
Many landslide areas in Colorado, both large and small, simply do not have
enough surface expression to be interpreted. Consequently, Landsat imagery
is not recommended as a routine landslide mapping tool, particularly if
higher resolution imagery or photography is available.
However, some areas of landsliding displayed chcracteristic evidence
that would be obvious to even the casual observer. This suggests that in
areas where landsliding is large-scale, where other geologic conditions are
relatively uniform, and where there is a need for frequent monitoring of
landslide activity, Landsat imagery .:.ay be the best tool available.
-5-
PUBLICATIONS
No project-funded publications were prepared during the report period.
RECO%ZMNbATIONS
No specific recommendations are necessary at this time.
-6-


Application of LANDSAT data to delimitation of avalanche hazards in Montane Colorado

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