Smartphone
Avalanche Search Apps—A Review
James
Floyer, PhD
Senior
Forecaster: Canadian Avalanche Centre
Discussion
paper: October, 2013
Introduction
Smartphones
are popular—in Canada, around 56% of people use one1.
Recently, apps have appeared on
the
market designed to allow one smartphone to search for another in
avalanche rescue scenarios. In this
way,
users are given avalanche victim search functionality on their
handheld device. There are currently
three
apps available: iSis Intelligent (Mountain) Rescue System; Snøg
Avalanche Buddy; and SnoWhere.
The
iSis and Snøg apps are available for iPhone only. SnoWhere is an
Android only app. Such apps are
referred
to as smartphone
avalanche search apps.
This
paper presents a technical discussion of the operation and
limitations of these devices. The suitability
of
this technology is analysed from a public safety point of view.
Existing literature was reviewed and app
developers
were contacted to provide detail on how their systems work as well as
test results2.
Technical
and
rescue experts were consulted for specific advice. No field testing
was carried out as part of this
review,
and details of how the systems work are gleaned in part through
marketing literature, including
videos
posted on developers’ websites, and in part through theoretical
considerations. Note also, at the
time
of preparation, no independent tests or reviews were available.
How
they work
Smartphone
avalanche search apps make use of various two‐way communication
technologies including:
cell
network; WiFi; and Bluetooth. Additionally, two of the apps make use
of GPS signals. Each app uses a
slightly
different set of technologies to communicate its location to another
smartphone, which must also
have
the identical app installed. Table 1 lists the technologies the
different apps make use of.
When
searching using WiFi or Bluetooth signals, a smartphone app permits
searches in a similar way to an
older‐style
analogue avalanche transceiver. Signal strength may be displayed as a
number (SnoWhere) or
on
a bar chart (Snøg), with an increase in signal strength indicating
increasing proximity to the victim.
Signal
direction is poorly resolved, as smartphones only have one antenna
(per communication
technology),
and the orientation of that antenna may not be known to the user.
The
SnoWhere and iSis apps use GPS to aid search location. The location
of the victim shows up on a
basemap,
allowing the searcher to use mapping functions to guide them towards
the victim.
Two
apps also include functionality that notifies other rescuers of an
avalanche incident either
automatically
(iSis) or manually (SnoWhere). These features could be useful within
the broader context of
search
and rescue, including avalanche search and rescue. However, since
this paper focuses on the victim
search
functionality of smartphone avalanche search apps, these features are
not considered further here.
1
Google
Report: Our Mobile Planet – Understanding the Mobile Consumer.
Ipsos MediaCT. May 2013.
2
Two
of the three app developers: Piranha Stuff BV (Snøg’s developers)
and Charcoal Frost Ltd (SnoWhere’s
developers)
responded to our enquiries.
Table
1: Summary of search and communication technologies employed by three
avalanche search apps.
App
Primary search (Range) Fine search Notification
iSis
(iPhone
4/5)
GPS
location sent by WiFi or cell
internet
connection (1000 m claimed)
or
direct via Bluetooth (45 m claimed)
Micro‐grid
search
using
Bluetooth
Automatic
(using trajectory
analysis)
alert from victim or
manual
alert from rescuer
Snøg
(Android)
WiFi
signal strength analysis (50 m
claimed)
Same
as primary None
SnoWhere
(iPhone
3/4/5)
GPS
location sent by Bluetooth (40 m
claimed
for iPhone 3, 45 m for iPhone
4
and 5)
Map‐assisted
Bluetooth
signal
strength
analysis
Rescuer
can share location
using
email or SMS
Range
issues
WiFi
and Bluetooth signals are strongly affected by transmission through
water‐based mediums, including
snow.
Therefore, signal strength is reduced when the transmitting device is
buried in an avalanche; this
effect
is amplified if the debris is dense and moist—often the case for
all but the smallest avalanches.
Signal
strength is also affected by the presence of trees, rocks or the
victim’s own body lying over the top
of
their phone.
In
their marketing materials, developers report ranges of between 40 and
50 m for WiFi/Bluetooth
searches.
These ranges likely reflect best case scenarios for relatively
shallow burials, or devices placed on
the
surface of the snow. Snøg Avalanche Buddy developers have reported
that forested terrain presents
difficulties
for WiFi transmission. Effective range was reduced to around 12 m
during their tests in
forested
terrain. While independent tests have not been carried out, similar
range reductions might be
expected
for deep burials in avalanche debris, and/or when the device is
shielded by a victim’s body.
Similar
range reductions are expected for Bluetooth signals.
GPS
accuracy is insufficient for precise victim location. SnoWhere
developers claim a “best reported
accuracy”
of 5 m with an iPhone 4/5. Accuracy values of 7.5 to 15 m are
probably more realistic for
devices
buried under 2 m of snow, since GPS performance degrades rapidly with
burial depth3.
Searchers
will
still have to switch to WiFi/Bluetooth signal search mode for the
fine search phase. If the GPS is not
already
switched on and tracking (which requires considerable battery power),
it may take some time to
acquire
a signal when buried, if it is able to do so at all.
GPS
technology offers, at best, a coarse search feature to bring the
searcher to within approximately 10 m
of
the victim. At worst, if a GPS location were incorrect, searchers
could actually be led away from the
victim,
believing they were moving closer towards them.
Compatibility
International
standards4
dictate
avalanche transceivers transmit and receive at a frequency of 457
kHz.
Regardless
of brand, all current avalanche transceivers are compatible with each
other. Compatibility
3
Schleppe,
J. and Lachapelle, G. GPS Tracking Performance under Deposited Snow.
ION GNSS, Sept. 2006.
4
ETSI
EN 300 718‐1 V1.2.1. Electromagnetic compatibility and Radio
spectrum Matters (ERM); Avalanche Beacons;
Transmitter‐receiver
systems; Part 1: Technical characteristics and test methods. European
Standard
(Telecommunications
series). May 2001.between
transceivers is a fundamental tenet of avalanche rescue; even older
analogue transceivers5
operate
on the 457 kHz frequency and are compatible with more recent digital
models6.
In
contrast, smartphones do not transmit at 457 kHz and therefore do not
(and cannot) adhere to
international
transceiver standards, regardless of what software is installed. They
are not compatible with
457
kHz avalanche transceivers.
Further,
smartphone avalanche search apps are not compatible with each other.
This means all members
of
a backcountry party must use the same smartphone platform with the
same software installed to have
a
useable rescue system. This creates heightened potential for someone
to assume they have a
compatible
smartphone device, while in actual fact they have a different and
incompatible device to the
ones
used by their companions. This incompatibility with existing
avalanche transceivers and lack of intercompatibility
between
the apps makes these applications, at their current level of
development,
particularly
inadequate from an avalanche rescue perspective.
Battery
life
Battery
life is another critical limitation with the current state of
smartphone technology. International
standards
for avalanche transceivers dictate that devices should be able to
transmit for 200 hours at
+10°C
and then still have enough power to search for 1 hour at ‐10°C.
Many smartphone batteries do not
last
for a full day of use on one charge, especially when power intensive
features, such as GPS location,
Bluetooth
or WiFi communication modes are employed. Battery drain is higher in
areas with no cell
coverage,
as phones constantly seek a signal. The effect of the cold further
reduces battery life. Many
phones
(including iPhone models) do not have user‐replaceable batteries.
SAR
groups report rescue victims frequently have trouble communicating
with rescuers at the end of the
day
as their smartphones run out of battery power. AdventureSmart,
Canada’s national SAR prevention
program,
recommends users switch their phones off to conserve battery power in
case of emergency
situations.
Users of smartphone avalanche search apps potentially face an
unacceptable choice: switch
their
phone off to conserve battery power for communication but disable
their avalanche safety device, or
maintain
power to their avalanche safety device but run the risk of not having
effective communication
for
emergency rescue use.
Robustness,
reliability and ease of use
International
avalanche transceiver standards include stringent drop and immersion
tests that must be
passed
before any device comes to market. Additionally, devices must include
a carrying system designed
to
guard against being ripped off during an avalanche. While some
smartphone models are reasonably
robust,
many are not, and may be susceptible to water ingress or shock. While
smartphone operating
systems
are generally good, software crashes do occur, sometimes requiring a
reboot; these may be
caused
by other installed software and not necessarily the avalanche search
app itself. If this were to
happen
during a rescue, valuable search time would be lost. Phones are not
supplied with a carrying
(457
kHz was adopted by the International Commission for Alpine Rescue
(IKAR) in 1986. Some models
manufactured
before that date operated at 2.275 kHz and are not compatible with
457 kHz transceivers.
6
The
Canadian Avalanche Centre recommends the exclusive use of 3‐antenna
digital transceivers (with no brand
preference),
due to their increased performance in a range of burial
scenarios)system, increasing
the possibility of the device becoming detached from the victim
during an avalanche,or dropped in the snow during a search.
Most
smartphones rely on touch screens, which are not operable wearing
thick gloves or mittens and may
not
work effectively if the screen is covered with snow or water. The
large size of screens creates
vulnerability,
as they might be easily cracked. To their credit, app developers
appear to have favoured
relatively
simple interfaces for their software; however, it may still be
necessary to navigate a menu
system,
or turn additional software or phone features off to properly operate
the avalanche search app.
There
is the possibility for distraction from an incoming call, email or
text during a search, which might be
less
easily ignored if the smartphone is in use in the rescuer’s hand
rather than stashed away in a pocket
or
backpack.
Interference
Recent
studies7,8
have
analysed the effects of interference on avalanche transceiver
performance for a
range
of devices including cell phones. Based on these studies, the
Canadian Avalanche Centre
recommends
the following separation distances between an avalanche transceiver
and other electronic
devices:
Transmit
mode (Send): 20 cm
Search
mode (Receive): 50 cm
It
is not known for certain whether dedicated avalanche transceivers
would experience additional
problems
if used in proximity to smartphones running avalanche search apps.
However, since
WiFi/Bluetooth
frequencies (~2.4 GHz) are quite different from the 457 kHz
frequency, the risk of
additional
interference from the proximal use of these apps is probably low.
(Note: as previously stated,
smartphone
avalanche search apps are NOT compatible with 457 kHz transceivers.
The discussion here is
whether
the incidental use of such an app would have an impact on a search
between two or more
dedicated
457 kHz transceivers.)
Interference
between Bluetooth and WiFi signals has been documented and occurs
because the operating
frequencies
are close together. This should not pose a problem if only one
communication technology is
used
at any one time and the other transmitting mode is switched off.
However, other installed apps, or
features
activated by the user may turn WiFi or Bluetooth signals on,
increasing the possibility of
interference.
Other possible sources of interference are receiving a cell phone
call and using the GPS
receiver
and other Bluetooth‐enabled electronic devices carried by users,
such as cameras, headphones
etc.—the
effect of these on smartphone search app performance is currently
unknown.
Marketing
Avalanche
search apps are being actively marketed as software that turns a
smartphone into an avalanche
transceiver.
None of the developers claim the software/phone combination will
adhere to international
transceiver
standards. In fact, at least two developers have specific disclaimers
that tell the user the
system
is not certified and does not meet international standards for
avalanche transceivers. Despite the
7
Barkhausen,
J. The Effect of External Interference on Avalanche Transceiver
Functionality. In Proceedings
International
Snow Science Workshop (ISSW 2012). Anchorage, AK, USA, Sept. 2012.
8
Genswein,
M., Atkins, D., Obad, J., Grady, E., Piche, M., Guyn, T., Whelan, R.
and Brattlien, K. Recommendation on
how
avoid Interference Issues in Companion and Organized Avalanche
Rescue. 2013.
Box
2759, Revelstoke, BC V0E 2S0 ph: (250) 837-2141 / fax: 1-866-366-2094
info@avalanche.ca / www.avalanche.ca
disclaimers,
the marketing intentions are quite clear from text, videos and
discussions on developer’s web
pages,
Facebook accounts, and other communications: these apps are being
touted specifically for use in
finding
buried victims in the event of an avalanche.
One
marketing statement from the Google Play store about the Snøg
Avalanche Buddy states: “Snøg is a
‘missing
person tracker’ tool. A tool designed to quickly locate and find a
victim, buried under an
avalanche.”
SnoWhere developers include this personal avalanche connection
statement: “20 years ago
our
founder was buried in an avalanche within bounds in poor visibility.
He only survived because he was
quickly
discovered by a passing boy who thought he had found a hat. That
experience inspired SnoWhere:
to
help ensure no‐one else’s survival relies on luck.” iSis
developers are probably the most aggressive in
pitching
their app as a dedicated avalanche rescue system, and include a
professionally edited video9
containing
a mock avalanche incident with a group of skiers who have apparently
left the confines of the
resort.
The incident is complete with images of a skier triggering an
avalanche and being buried by snow,
before
his companions use their phone with the iSis app to rescue the
victim.
Legal
and ethical issues
While
it is clear that avalanche search apps are being actively marketed as
software that enables
smartphones
to be used as avalanche search devices, the legal status of
marketing/selling an app that
turns
an otherwise compliant smartphone into an avalanche search device
that does not meet
international
standards is unclear. Additionally, it is not a simple matter to
establish whether international
standards
for avalanche transceivers are binding or voluntary in the Canadian
context. Specific legal
advice
would be required to establish these points in Canada.
Regardless
of legal state, developers do have an ethical obligation to ensure
products they bring to market
do
not have a negative impact on public safety. For a lifesaving device
with mission‐critical operating
parameters
that relies on successful communication with other similar devices,
independent testing in
real‐world
scenarios is imperative. None has been made available to us, and to
our knowledge none has
yet
been carried out. The numerous and serious flaws in the current state
of smartphone avalanche
search
app technology give justifiable cause for concern that public safety
may be compromised by the
introduction
of this kind of avalanche rescue device.
Conclusion
and discussion
The
CAC does not consider any of the existing apps discussed here to be
viable devices for avalanche
companion
rescue. There are serious concerns and vulnerabilities with a range
of important aspects of the
technology.
The most critical of these are:
lack
of compatibility with existing avalanche transceivers
lack
of compatibility between different operating systems and software
brands
smartphone
battery life
range
concerns in real‐world scenarios (i.e. when buried in avalanche
debris)
Additional
concerns are: system robustness; smartphone reliability; ease of use;
interference issues; and
the
possibility of distraction during a search.
9
http://www.youtube.com/watch?v=qpqnszYXdmg&feature=player_embedded
Box
2759, Revelstoke, BC V0E 2S0 ph: (250) 837-2141 / fax: 1-866-366-2094
info@avalanche.ca / www.avalanche.ca
There
are good reasons for having in place international standards for
avalanche transceivers. Of course,
standards
may change and evolve with time to reflect new technologies. But this
must be done in a
transparent,
collaborative manner that maintains at its core the best interests of
public safety. Present
development
of smartphone avalanche rescue apps appears haphazard, is
unregulated, and is potentially
dangerous
to end users, who may confuse this technology with legitimate
avalanche transceivers. The
option
to spend only a few dollars on a cheap app in place of spending
several hundreds of dollars on a
dedicated
avalanche transceiver may be tempting to many, particularly novice
users. However, the choice
to
use such an app as a safety device when entering avalanche terrain
could imperil all members of the
user’s
backcountry group.
Some
may argue that the ubiquity of smartphone devices might make up for
the shortfall in performance
of
avalanche search apps. Under this pretext, the likelihood of an
avalanche victim being without any form
of
avalanche rescue device is lower, which compensates for any reduced
search performance. This
argument
is invalid for the following reasons.
First,
the critical issues of cross‐compatibility, inter‐compatibility,
poor battery life and range
under
avalanche debris preclude any kind of benefit from smartphone
ubiquity.
Second,
apps must be manually installed and activated, so smartphone ubiquity
does not equate
to
a ubiquity of avalanche search devices.
Third,
on account of the urgency of avalanche companion rescue with target
rescue times (i.e. the
combination
of searching, pinpoint location using a probe and extrication by
digging) of 10
minutes
or less10,
substandard avalanche search devices are likely to have a
considerable negative
impact
on victim mortality.
Fourth,
there is potential for a significant negative impact on users of
dedicated avalanche
transceivers
by the presence of smartphone avalanche search app technology: that
is the
possibility
for people who would have otherwise purchased (or borrowed or rented)
a dedicated
avalanche
transceiver to be tempted to download an app onto their smartphone
instead. These
people
may not be aware their smartphone search app is not compatible with
other group
member’s
dedicated avalanche transceivers, so putting themselves and their
companions at risk.
Recommendations
In
light of the deficiencies of current smartphone avalanche search app
technology, the Canadian
Avalanche
Centre is implementing the following strategies:
1.
Maintain the prevailing culture of using dedicated 457 kHz
avalanche transceivers during winter
backcountry
recreation by continuing to promote the Canadian Avalanche Centre’s
and other
partners’
existing awareness campaigns that recommend the use of dedicated
avalanche
transceivers,
probes and shovels for all group members.
2.
Discourage
the adoption of smartphone avalanche search app technology in
place of dedicated
457
kHz transceivers. This might take the form of targeted education
campaigns directed at
specific
user groups. Campaigns should highlight the benefits to users of
dedicated 457 kHz
transceivers
over smartphone avalanche search apps.
10
Haegeli,
P., Falk, M., Brugger, H., Etter, H‐J. Comparison of avalanche
survival patterns in Canada and Switzerland.
Canadian
Medical Association Journal. doi: 10.1503/cmaj.101435. Mar. 2011.
Box
2759, Revelstoke, BC V0E 2S0 ph: (250) 837-2141 / fax: 1-866-366-2094
info@avalanche.ca / www.avalanche.ca
3.
Respond to media and public enquiries regarding this new
technology, including being prepared
to
respond in the event of an incident involving avalanche search apps,
either in Canada or
elsewhere.
4.
Advocate that new avalanche search technologies, especially those
that deviate from agreedupon
international
standards, be developed collaboratively, thoroughly and with
transparency.
Developers
must be reminded of their ethical obligation to ensure full and
independent testing of
their
rescue systems prior
to
going to market.
